1. JEEP OBD1 TROUBLE
CODES LIST
Compiled by
www.obdcodex.com

2. Code 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.
Code 12 Battery or computer recently disconnected
Code 13
MAP sensor or vacuum line may not be
working
Code 13 No change in MAP from "Start" to "Run"
Code 14 MAP sensor voltage below .16V or over 4.96V
Code 15 No speed/distance sensor signal
Code 16
Loss of battery voltage detected with engine
running
Code 17 Engine stays cool too long
Code 17 Knock sensor circuit
Code 21
Oxygen sensor signal doesn't change (stays at
4.3-4.5V). Probably bad oxygen sensor.
Code 21
Oxygen sensor signal shorted to voltage.
Probably bad oxygen sensor.
Code 22
Coolant sensor signal out of range - May have
been disconnected to set timing
Code 23 Incoming air temperature sensor may be bad
Code 24 Throttle position sensor over 4.96V
Code 25
Automatic Idle Speed (AIS) motor driver circuit
shorted or target idle not reached
Jeep OBD1 Codes List 1
Code Definition

3. Code 26
Peak injector circuit voltage has not been
reached (need to check computer signals,
voltage reg, injectors)
Code 27
Injector circuit isn't switching when it's told to
(TBI)
Code 27 Injector circuit #1 not switching right
Code 27 Injector circuit #2 not switching right
Code 27
Injector output driver not responding - check
computer, connections
Code 31 Bad evaporator purge solenoid circuit or driver
Code 32 Power loss/limited lamp or circuit
Code 32
EGR gases not working (1988) - check vacuum,
valve
Code 32
Computer didn't see change in air/'fuel ratio
when EGR activated - check valve, vacuum
lines, and EGR electrical
Code 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)
Code 34 EGR solenoid circuit shorted or open
Code 34 Speed control shorted or open
Code 35 Cooling fan relay circuit open or shorted
Code 35 Idle switch motor fault - check connections
Jeep OBD1 Codes List 2
Code Definition

4. Code 36 Wastegate control circuit open or shorted
Code 37 Shift indicator light failure, 5-speed
Code 37 Part throttle lock/unlock solenoid driver circuit
Code 37 Solenoid coil circuit
Code 37 Trans temperature sensor voltage low
Code 41 Alternator field control circuit open or shorted
Code 42
Automatic shutdown relay circuit open or
shorted
Code 42 Fuel pump relay control circuit
Code 42 Fuel level unit - no change over miles
Code 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)
Code 43
Peak primary coil current not achieved with
max dwell time
Code 43 Cylinder misfire
Code 43
Problem in power module to logic module
interface
Code 44 No FJ2 voltage present at logic board
Code 44
Logic module self-diagnostics indicate
problem
Jeep OBD1 Codes List 3
Code Definition

5. Code 44 Battery temperature out of range
Code 45
Turbo boost limit exceeded (engine was shut
down by logic module)
Code 46
Battery voltage too high during charging or
charging system voltage too low
Code 47
Battery voltage too low and alternator output
too low
Code 51 Oxygen sensor stuck at lean position
Code 51 Internal logic module fault
Code 52 Oxygen sensor stuck at rich position
Code 52 Internal logic module fault
Code 53 Logic module internal problem
Code 54 No sync pickup signal during engine rotation
Code 54
Internal logic module fault ('84 turbo only) - or
camshaft sensor/distributor timing
Code 55 End of codes
Code 61 "Baro" sensor open or shorted
Code 62 EMR mileage cannot be stored in EEPROM
Code 62 PCM failure SRI mile not stored
Code 63 Controller cannot write to EEPROM
Code 64 Catalytic converter efficiency failure
Jeep OBD1 Codes List 4
Code Definition

6. Code 65 Power steering switch failure
Code 66
No CCD Message From TCM and/or No CCD
Message From BCM
Code 76 Fuel pump ballast bypass relay circuit
Jeep OBD1 Codes List 5
Code Definition