GM OBD1 Codes

DTC - 12 No distributor reference pulse (diagnostic test active)

DTC - 13 Oxygen sensor circuit open or no activity

DTC - 13 Left bank O2 sensor circuit open or no activity

DTC - 14 Engine coolant temp sensor error (high temp indicated)

DTC - 15 Engine coolant temp sensor error (low temp indicated)

DTC - 16 System voltage too low

DTC - 17 Camshaft position sensor error

DTC - 21 Throttle Position sensor error (signal high)

DTC - 22 Throttle position sensor error (signal low)

DTC - 23 Intake air temp sensor error (low temp indicated)

DTC - 24 Vehicle speed sensor error (open circuit or no activity)

DTC - 25 Intake air temp sensor error (high temp indicated)

DTC - 26 Quad Driver Module (QDM A) error

DTC - 28 Auto transmission range pressure switch error

DTC - 31 Wastegate solenoid circuit error

DTC - 31 Gear Position Switch (PRNDL) error

DTC - 32 EGR system failure

DTC - 33 MAP sensor circuit error (signal high indicating low vacuum)

DTC - 34 MAP sensor circuit error (signal low indicating high vacuum)

DTC - 35 IAC problem or idle error

DTC - 36 MAF sensor error

DTC - 36 24x Crankshaft position sensor circuit error

DTC - 36 4T60-E Shifting Error

DTC - 37 TCC brake switch circuit error

DTC - 38 TCC brake switch circuit error

DTC - 39 Clutch switch circuit error

DTC - 39 TCC error