TJ Computer Codes

11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. Can cause the engine to stop working entirely with no limp-home mode.

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?)

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, vacuum leak found

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

32 EGR gases not working (1988) - check vacuum, valve

32 (1990-92, all but Turbo) 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)

34 (1984-86) EGR solenoid circuit shorted or open

34 (1987-1991) speed control shorted or open

35 Cooling fan relay circuit open or shorted

35 (trucks) idle switch motor fault - check connections

36 (turbo) Wastegate control circuit open or shorted

36 (3.9/5.2 RWD) solenoid coil circuit (air switching)

36 (Turbo IV) #3 Vent Solenoid open/short

37 Shift indicator light failure, 5-speed
OR
part throttle lock/unlock solenoid driver circuit (87-89)
OR
solenoid coil circuit (85-89 Turbo I-IV)
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

42 Fuel pump relay control circuit

42 Fuel level unit - no change over miles  OR  Z1 voltage missing when autoshutdown circuit energized

43 Peak primary coil current not achieved with max dwell time OR 43 Cylinder misfire OR Problem in power module to logic module interface

44 No FJ2 voltage present at logic board OR Logic module self-diagnostics indicate problem OR 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 (Bob wrote: may be tripped by a bad EGR system causing a rich condition, and the O2 sensor trying to compensate. The O2 sensor may still be good. The EGR assembly consists of two pieces, the valve and the vacuum transducer (round plastic unit with cylinder on top and both electrical and vacuum connections)   OR  Internal logic module fault ('84 turbo only).

52 Oxygen sensor stuck at rich position  OR   Internal logic module fault ('84 turbo only)

53 Logic module internal problem

54 No sync pickup signal during engine rotation (turbo only)  OR  Internal logic module fault ('84 turbo only) - or camshaft sensor/distributor timing (7)

55 End of codes

61 "Baro" sensor open or shorted

62 EMR mileage cannot be stored in EEPROM  OR  PCM failure SRI mile not stored

63 Controller cannot write to EEPROM

64 Catalytic converter efficiency failure

65 Power steering switch failure

88 Start of test (not usually given, don't expect it)