OBD1 Diagnostic Trouble Codes
In the 80's General Motors implemented an interface and a protocol for testing the Engine control unit for the vehicles on the assembly line. This protocol will known as ALDL which first comunicated with 160 baude rate and with pulse-width modulation; later 1986 this protocol was upgraded to 8192 baud and half-duplex signaling. Finaly in 1991 the California Air Resource Board declaires that all new vehicles sold in Calofornia should have some basic OBD functions. After the introduction of the OBD 2 this first on board dignostic systems will be called OBD 1.
Here are the OBD1 Trouble 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
DTC – 41 Ignition control error
DTC – 41 MEM-CAL error
DTC – 41 C³I Cam Sensor Signal error
DTC – 42 Ignition bypass circuit error
DTC – 43 Knock sensor error
DTC – 44 Oxygen sensor error (lean condition indicated)
DTC – 44 Left bank O2 sensor error (lean condition indicated)
DTC – 45 Oxygen sensor error (rich condition indicated)
DTC – 45 Left bank O2 sensor error (rich condition indicated)
DTC – 46 Pass-Key II (VATS) system error – circuit out of freq range
DTC – 47 UART (serial data) circuit error
DTC – 51 PROM error
DTC – 51 Incorrect MEM-CAL
DTC – 52 Fuel cal-pak incorrect or missing
DTC – 53 System voltage too high
DTC – 53 Digital EGR Valve solenoid 1 error
DTC – 54 Fuel pump circuit low voltage
DTC – 54 Digital EGR Valve solenoid 2 error
DTC – 55 ECM error
DTC – 55 Digital EGR Valve solenoid 3 error
DTC – 56 Quad Driver Module (QDM B) error
DTC – 57 Boost Control error
DTC – 58 Trans fluid temp sensor circuit error (low voltage)
DTC – 58 VATS system error
DTC – 59 Trans fluid temp sensor circuit error (high voltage)
DTC – 61 A/C system performance
DTC – 63 Right bank O2 sensor circuit error
DTC – 63 MAP sensor circuit signal voltage high (low vacuum indicated)
DTC – 64 Right bank O2 sensor lean exhaust indicated
DTC – 64 MAP sensor circuit signal voltage low (high vacuum indicated)
DTC – 65 Right bank O2 sensor rich exhaust indicated
DTC – 66 A/C pressure sensor circuit error (low pressure indicated)
DTC – 67 A/C pressure sensor circuit error
DTC – 68 A/C clutch relay circuit error (shorted to ground)
DTC – 69 A/C clutch relay circuit error (open circuit indicated)
DTC – 69 A/C high pressure switch error
DTC – 70 A/C pressure sensor circuit error (high pressure indicated)
DTC – 71 A/C evaporator temp sensor circuit error (low temp indicated)
DTC – 72 VSS signal circuit error
DTC – 73 A/C evaporator temp sensor circuit error (high temp indicated)
DTC – 75 Digital EGR solenoid #1 circuit error
DTC – 76 Digital EGR solenoid #2 circuit error
DTC – 77 Digital EGR solenoid #3 circuit error
DTC – 79 Transmission fluid overtemp
DTC – 80 Transmission component slipping
DTC – 82 3x Crankshaft position sensor circuit error
DTC – 85 PROM error
DTC – 86 A/D error
DTC – 87 EEPROM error (flash memory error)
DTC – 90 TCC error
DTC – 93 Transmission pressure control solenoid circuit error
DTC – 96 Transmission system voltage low
DTC – 98 Invalid PCM program
DTC – 99 Invalid PCM program