1991-1995 Jeep Wrangler (YJ) Trouble Codes
| Code |
Probable
Cause
|
11
|
Ignition
|
13
|
Manifold Absolute Pressure (MAP)
Sensor Vacuum
|
14
|
Manifold Absolute Pressure (MAP)
Sensor Electrical
|
15
|
Distance sensor or circuit
|
17
|
Engine running too cool
|
21
|
Oxygen sensor or circuit
|
22
|
Coolant temperature sensor or
circuit
|
23
|
MAT sensor or circuit
|
24
|
Throttle Position Sensor (TPS)
sensor or circuit
|
25
|
Automatic Idle Speed (AIS)
circuit
|
27
|
Fuel injector control
|
31
|
EVAP solenoid or circuit
|
33
|
Air conditioning clutch relay
|
41
|
Alternator field
|
42
|
Automatic shutdown relay
|
44
|
Battery temperature sensor
|
46
|
Battery over voltage
|
47
|
Battery under voltage
|
51
|
Oxygen sensor - lean condition
|
52
|
Oxygen sensor - rich condition
|
53
|
Internal engine controller fault
|
54
|
Distributor sync pickup
|
55
|
End of Code output
|
62
|
Emissions Maintenance Reminder
(EMR) mileage accumulator
|
63
|
Controller failure EEPROM write
denied
|
The
diagnostic trouble codes on
all models can be extracted from the
Powertrain Control Module (PCM) using a SCAN tool. On 1991 through 1995
models only, the PCM can be placed in the diagnostic mode and the
trouble codes flashed on the Check Engine light.
The
PCM will illuminate the
CHECK ENGINE light on the dash if it
recognizes a fault in the system. The light will remain lit until the
problem is repaired and the code cleared or the PCM does not detect any
malfunction for several consecutive drive cycles.
To
extract the diagnostic
trouble codes, perform the following steps:
- Without starting the engine, turn
the ignition key ON, OFF, ON,
OFF and ON. The CHECK ENGINE light on the dash will begin to flash.
- If any trouble codes are stored in
the PCM memory, the CHECK
ENGINE light will flash the number of the first digit, pause and flash
the number of the second digit. For example, Code 23, air temperature
sensor circuit would be indicated by two flashes, pause three flashes.
A long pause will appear between individual codes if more than one code
is present. Carefully observe the flashes and record the exact code
number(s) onto paper.
- After the stored codes have been
indicated (or if everything in
the self diagnosis system is functioning properly), the CHECK ENGINE
light will flash a Code 55.
- If the ignition key is turned OFF
during the code extraction
process and possibly turned back ON, the self diagnostic system will
automatically invalidate the procedure and must be restarted.
