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GM Fault Codes

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Note: This page may contain community-sourced information and/or data from manufacturer manuals. Descriptions, probable causes, and default actions can vary by year or ECU calibration and may include inaccuracies. Always verify using official manufacturer documentation or trusted service information.
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Community-sourced list Unverified • from online forum
Code Description Info
12Diagnostic test active
↗

Probable cause

    Default action

      Source: Community forum list (unverified)
      13Oxygen sensor circuit open or no activity
      ↗

      Probable cause

        Default action

          Source: Community forum list (unverified)
          13Left bank O2 sensor circuit open or no activity
          ↗

          Probable cause

            Default action

              Source: Community forum list (unverified)
              14Engine coolant temp sensor error (high temp indicated)
              ↗

              Probable cause

                Default action

                  Source: Community forum list (unverified)
                  15Engine coolant temp sensor error (low temp indicated)
                  ↗

                  Probable cause

                    Default action

                      Source: Community forum list (unverified)
                      16System voltage too low
                      ↗

                      Probable cause

                        Default action

                          Source: Community forum list (unverified)
                          17Camshaft position sensor error
                          ↗

                          Probable cause

                            Default action

                              Source: Community forum list (unverified)
                              21Throttle Position sensor error (signal high)
                              ↗

                              Probable cause

                                Default action

                                  Source: Community forum list (unverified)
                                  22Throttle position sensor error (signal low)
                                  ↗

                                  Probable cause

                                    Default action

                                      Source: Community forum list (unverified)
                                      23Intake air temp sensor error (low temp indicated)
                                      ↗

                                      Probable cause

                                        Default action

                                          Source: Community forum list (unverified)
                                          24Vehicle speed sensor error (open circuit or no activity)
                                          ↗

                                          Probable cause

                                            Default action

                                              Source: Community forum list (unverified)
                                              25Intake air temp sensor error (high temp indicated)
                                              ↗

                                              Probable cause

                                                Default action

                                                  Source: Community forum list (unverified)
                                                  26Quad Driver Module (QDM A) error
                                                  ↗

                                                  Probable cause

                                                    Default action

                                                      Source: Community forum list (unverified)
                                                      28Auto transmission range pressure switch error
                                                      ↗

                                                      Probable cause

                                                        Default action

                                                          Source: Community forum list (unverified)
                                                          31Wastegate solenoid circuit error / Gear Position Switch (PRNDL) error
                                                          ↗

                                                          Probable cause

                                                            Default action

                                                              Source: Community forum list (unverified)
                                                              32EGR system failure
                                                              ↗

                                                              Probable cause

                                                                Default action

                                                                  Source: Community forum list (unverified)
                                                                  33MAP sensor circuit error (signal high / low vacuum)
                                                                  ↗

                                                                  Probable cause

                                                                    Default action

                                                                      Source: Community forum list (unverified)
                                                                      34MAP sensor circuit error (signal low / high vacuum)
                                                                      ↗

                                                                      Probable cause

                                                                        Default action

                                                                          Source: Community forum list (unverified)
                                                                          35IAC problem or idle error
                                                                          ↗

                                                                          Probable cause

                                                                            Default action

                                                                              Source: Community forum list (unverified)
                                                                              36MAF sensor error / 24x Crank sensor circuit / 4T60-E shifting error
                                                                              ↗

                                                                              Probable cause

                                                                                Default action

                                                                                  Source: Community forum list (unverified)
                                                                                  37TCC brake switch circuit error
                                                                                  ↗

                                                                                  Probable cause

                                                                                    Default action

                                                                                      Source: Community forum list (unverified)
                                                                                      38TCC brake switch circuit error
                                                                                      ↗

                                                                                      Probable cause

                                                                                        Default action

                                                                                          Source: Community forum list (unverified)
                                                                                          39Clutch switch circuit error / TCC error
                                                                                          ↗

                                                                                          Probable cause

                                                                                            Default action

                                                                                              Source: Community forum list (unverified)
                                                                                              41Ignition control error / MEM-CAL error / C³I cam sensor signal error
                                                                                              ↗

                                                                                              Probable cause

                                                                                                Default action

                                                                                                  Source: Community forum list (unverified)
                                                                                                  42Ignition bypass circuit error
                                                                                                  ↗

                                                                                                  Probable cause

                                                                                                    Default action

                                                                                                      Source: Community forum list (unverified)
                                                                                                      43Knock sensor error
                                                                                                      ↗

                                                                                                      Probable cause

                                                                                                        Default action

                                                                                                          Source: Community forum list (unverified)
                                                                                                          44Oxygen sensor error (lean) / Left bank lean
                                                                                                          ↗

                                                                                                          Probable cause

                                                                                                            Default action

                                                                                                              Source: Community forum list (unverified)
                                                                                                              45Oxygen sensor error (rich) / Left bank rich
                                                                                                              ↗

                                                                                                              Probable cause

                                                                                                                Default action

                                                                                                                  Source: Community forum list (unverified)
                                                                                                                  46Pass-Key II (VATS) system error — circuit out of frequency range
                                                                                                                  ↗

                                                                                                                  Probable cause

                                                                                                                    Default action

                                                                                                                      Source: Community forum list (unverified)
                                                                                                                      47UART (serial data) circuit error
                                                                                                                      ↗

                                                                                                                      Probable cause

                                                                                                                        Default action

                                                                                                                          Source: Community forum list (unverified)
                                                                                                                          51PROM error / Incorrect MEM-CAL
                                                                                                                          ↗

                                                                                                                          Probable cause

                                                                                                                            Default action

                                                                                                                              Source: Community forum list (unverified)
                                                                                                                              52Fuel cal-pak incorrect or missing
                                                                                                                              ↗

                                                                                                                              Probable cause

                                                                                                                                Default action

                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                  53System voltage too high / Digital EGR valve solenoid 1 error
                                                                                                                                  ↗

                                                                                                                                  Probable cause

                                                                                                                                    Default action

                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                      54Fuel pump circuit low voltage / Digital EGR valve solenoid 2 error
                                                                                                                                      ↗

                                                                                                                                      Probable cause

                                                                                                                                        Default action

                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                          55ECM error / Digital EGR valve solenoid 3 error
                                                                                                                                          ↗

                                                                                                                                          Probable cause

                                                                                                                                            Default action

                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                              56Quad Driver Module (QDM B) error
                                                                                                                                              ↗

                                                                                                                                              Probable cause

                                                                                                                                                Default action

                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                  57Boost control error
                                                                                                                                                  ↗

                                                                                                                                                  Probable cause

                                                                                                                                                    Default action

                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                      58Trans fluid temp sensor circuit error (low voltage) / VATS system error
                                                                                                                                                      ↗

                                                                                                                                                      Probable cause

                                                                                                                                                        Default action

                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                          59Trans fluid temp sensor circuit error (high voltage)
                                                                                                                                                          ↗

                                                                                                                                                          Probable cause

                                                                                                                                                            Default action

                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                              61A/C system performance
                                                                                                                                                              ↗

                                                                                                                                                              Probable cause

                                                                                                                                                                Default action

                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                  63Right bank O2 sensor circuit error / MAP signal high (low vacuum)
                                                                                                                                                                  ↗

                                                                                                                                                                  Probable cause

                                                                                                                                                                    Default action

                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                      64Right bank O2 sensor lean / MAP signal low (high vacuum)
                                                                                                                                                                      ↗

                                                                                                                                                                      Probable cause

                                                                                                                                                                        Default action

                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                          65Right bank O2 sensor rich indicated
                                                                                                                                                                          ↗

                                                                                                                                                                          Probable cause

                                                                                                                                                                            Default action

                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                              66A/C pressure sensor circuit error (low pressure)
                                                                                                                                                                              ↗

                                                                                                                                                                              Probable cause

                                                                                                                                                                                Default action

                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                  67A/C pressure sensor circuit error
                                                                                                                                                                                  ↗

                                                                                                                                                                                  Probable cause

                                                                                                                                                                                    Default action

                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                      68A/C clutch relay circuit error (short to ground)
                                                                                                                                                                                      ↗

                                                                                                                                                                                      Probable cause

                                                                                                                                                                                        Default action

                                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                                          69A/C clutch relay circuit error (open) / A/C high pressure switch error
                                                                                                                                                                                          ↗

                                                                                                                                                                                          Probable cause

                                                                                                                                                                                            Default action

                                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                                              70A/C pressure sensor circuit error (high pressure)
                                                                                                                                                                                              ↗

                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                Default action

                                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                                  71A/C evaporator temp sensor circuit error (low temp)
                                                                                                                                                                                                  ↗

                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                    Default action

                                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                                      72VSS signal circuit error
                                                                                                                                                                                                      ↗

                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                        Default action

                                                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                                                          73A/C evaporator temp sensor circuit error (high temp)
                                                                                                                                                                                                          ↗

                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                            Default action

                                                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                                                              75Digital EGR solenoid #1 circuit error
                                                                                                                                                                                                              ↗

                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                                                  76Digital EGR solenoid #2 circuit error
                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                                                      77Digital EGR solenoid #3 circuit error
                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                                                                          79Transmission fluid overtemp
                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                                                                              80Transmission component slipping
                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                                                                  823x Crankshaft position sensor circuit error
                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                                                                      85PROM error
                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                                                                                          86A/D error
                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                                                                                              87EEPROM error (flash memory error)
                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                                                                                  90TCC error
                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                                                                                      93Transmission pressure control solenoid circuit error
                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                          Source: Community forum list (unverified)
                                                                                                                                                                                                                                                          96Transmission system voltage low
                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                              Source: Community forum list (unverified)
                                                                                                                                                                                                                                                              98Invalid PCM program
                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                  Source: Community forum list (unverified)
                                                                                                                                                                                                                                                                  99Invalid PCM program
                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                      Source: Community forum list (unverified)
                                                                                                                                                                                                                                                                      ATSG manual list Workshop manual • vetted source
                                                                                                                                                                                                                                                                      Code Description Info
                                                                                                                                                                                                                                                                      14Engine Temperature High
                                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                                          Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                          15Engine Temperature Low
                                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                                              Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                              21Throttle Position High
                                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                                  Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                  22Throttle Position Low
                                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                                      Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                      24Output Speed Low
                                                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                                                          Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                          28Pressure Switch Manifold
                                                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                                                              Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                              37Brake Switch Stuck “ON”
                                                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                                                  Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                  39TCC Stuck “OFF”
                                                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                                                      Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                      53System Voltage High
                                                                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                                                                          Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                          58Transmission Temperature High
                                                                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                                                                              Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                              59Transmission Temperature Low
                                                                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                                                                  Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                  68Overdrive Ratio
                                                                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                                                                      Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                      73Force Motor Current
                                                                                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                                                                                          Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                          75System Voltage Low
                                                                                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                                                                                              Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                              81Quad Driver and Shift Solenoid “B” Fault
                                                                                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                                                                                  Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                                  82Quad Driver and Shift Solenoid “A” Fault
                                                                                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                                                                                      Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                                      83Quad Driver and TCC Fault
                                                                                                                                                                                                                                                                                                                                      ↗

                                                                                                                                                                                                                                                                                                                                      Probable cause

                                                                                                                                                                                                                                                                                                                                        Default action

                                                                                                                                                                                                                                                                                                                                          Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                                          85Undefined Ratio
                                                                                                                                                                                                                                                                                                                                          ↗

                                                                                                                                                                                                                                                                                                                                          Probable cause

                                                                                                                                                                                                                                                                                                                                            Default action

                                                                                                                                                                                                                                                                                                                                              Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                                              86Shift Solenoid “B” Stuck “ON”
                                                                                                                                                                                                                                                                                                                                              ↗

                                                                                                                                                                                                                                                                                                                                              Probable cause

                                                                                                                                                                                                                                                                                                                                                Default action

                                                                                                                                                                                                                                                                                                                                                  Source: ATSG 4L80E Technical Manual
                                                                                                                                                                                                                                                                                                                                                  87Shift Solenoid “B” Stuck “OFF”
                                                                                                                                                                                                                                                                                                                                                  ↗

                                                                                                                                                                                                                                                                                                                                                  Probable cause

                                                                                                                                                                                                                                                                                                                                                    Default action

                                                                                                                                                                                                                                                                                                                                                      Source: ATSG 4L80E Technical Manual