Older Model Computer Codes (OBDI) - IMPORTANT! Codes may be different for newer vehicles starting circa 1996. 11 No ignition reference signal detected during cranking OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. 12 Battery or computer recently disconnected 13 MAP sensor or vacuum line may not be working 14 MAP sensor voltage below .16V or over 4.96V 15 No speed/distance sensor signal 16 Loss of battery voltage detected with engine running 17 Engine stays cool too long (bad thermostat or coolant sensor?) OR 17 (1985 turbo only): knock sensor circuit 21 Oxygen sensor signal doesn't change (stays at 4.3-4.5V). Probably bad oxygen sensor 22 Coolant sensor signal out of range - May have been disconnected to set timing 23 Incoming air temperature sensor may be bad 24 Throttle position sensor over 4.96V 25 Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached 26 Peak injector circuit voltage has not been reached (need to check computer signals, voltage reg, injectors) 27 Injector circuit isn't switching when it's told to (TBI) OR (MPI) injector circuit #1 not switching right OR (turbo) injector circuit #2 not switching right OR (all 1990-) injector output driver not responding - check computer, connections 31 Bad evaporator purge solenoid circuit or driver 32 (1984 only) power loss/limited lamp or circuit OR 32 EGR gases not working (1988) - check vacuum, valve OR 32 (1990-92) computer didn't see change in air/'fuel ratio when EGR activated - check valve, vacuum lines, and EGR electrical 33 Air conditioning clutch relay circuit open or shorted (may be in the wide-open-throttle cutoff circuit or normal on early 80's models if you don't have air conditioning) 34 (1984-86) EGR solenoid circuit shorted or open OR 34 (1987-1991) speed control shorted or open 35 Cooling fan relay circuit open or shorted OR 35 idle switch motor fault - check connections 36 (turbo only) Wastegate control circuit open or shorted 37 Shift indicator light failure, 5-speed OR part throttle lock/unlock solenoid driver circuit (87-89) OR solenoid coil circuit (85-87 Turbo only) OR Trans temperature sensor voltage low (1995 and on) 41 Alternator field control circuit open or shorted 42 Automatic shutdown relay circuit open or shorted OR 42 Fuel pump relay control circuit OR 42 Fuel level unit - no change over miles OR 42 Z1 voltage missing when autoshutdown circuit energized (The Z1 voltage is the voltage of the circuits fed by the autoshutdown relay. This typically includes fuel pump and switched-battery feed to the ignition coil) 43 Peak primary coil current not achieved with max dwell time OR 43 Cylinder misfire OR 43 Problem in power module to logic module interface 44 No FJ2 voltage present at logic board OR 44 Logic module self-diagnostics indicate problem OR 44 Battery temperature out of range 45 Turbo boost limit exceeded (engine was shut down by logic module) 46 Battery voltage too high during charging or charging system voltage too low 47 Battery voltage too low and alternator output too low 51 Oxygen sensor stuck at lean position (this may be tripped by a bad MAP sensor system causing a rich condition. If you get hot rough idle and stalling, especially on deceleration, accompanied by flooded engine and difficulty restarting, that can be a bad MAP sensor causing the O2 sensor to try to compensate. If you get poor cold driveability, stumbling and bucking, and acceptable warm driving with poor gas mileage (a drop of 10 mpg or more), that is usually the O2 sensor. OR 51 Internal logic module fault ('84 turbo only). 52 Oxygen sensor stuck at rich position OR 52 Internal logic module fault ('84 turbo only) 53 Logic module internal problem 54 No sync pickup signal during engine rotation (turbo only) OR 54 Internal logic module fault ('84 turbo only) - or camshaft sensor/distributor timing 55 End of codes 61 "Baro" sensor open or shorted 62 EMR mileage cannot be stored in EEPROM 62 PCM failure SRI mile not stored 63 Controller cannot write to EEPROM 64 Catalytic converter efficiency failure 65 Power steering switch failure 66 No CCD Message From TCM and/or No CCD Message From BCM