ABOUT JEEP

Chrysler Computer Codes
These only work if you have fuel injection. Otherwise, see the web site or the "troubleshooting electronic feedback carburetors" section.
Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. (On is *not* start!)

The "check engine" light will flash. Count the flashes Each code is a two digit code, so a (for example) 23 would be FLASH FLASH (pause) FLASH FLASH FLASH (loong pause)

It will never flash more than 9 times, watch for pauses! 55 is end of codes, 33 is normal if you don't have air conditioning.

When the computer indicates major failure, it will activate Limp In mode, which guesses about data to compensate for sensor failure.

Please note that some codes are NOT included below, this is not a complete listing, but it IS very close to complete.


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
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 (1985 turbo only knock sensor circuit
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 (SEE NOTE #3)
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)
(SEE NOTE #4 BELOW)
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 7-89)
OR
solenoid coil circuit 5-89 Turbo I-IV)
OR
Trans temparature sensor voltage low (1995 and on; see NOTE 2)

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
42 Z1 voltage missing when autoshutdown circuit energized (whatever
that means)
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 (see Note #1!)
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 (lean condition)
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)
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
88 Start of test (not usually given, don't expect it)

These codes cover multiple years and engines (2.2l, 2.5l, 3.0l).
NOTE #1.

The power module has an air-cooled resistor which is used to sense the
incoming air temperature. This information is fed to the logic module
and is used to control the duty cycle of the field current in the
alternator. This code applies ONLY to alternators whose voltage is
computer regulated. The battery voltage is sensed by the logic module
-- there is an internal takeoff from the wire feeding the NVRAM
keep-alive power circuit which is fed to a voltage comparator. So...if
you lose the feed to keep RAM information stored when the engine's off,
you also lose battery voltage sensing. -- Bohdan Bodnar

NOTE #2

From the 1995 TRUCK (Ram) manuals: the trailer towing package includes a
transmission coolant temp sensor while the standard package doesn't. I
imagine that the fault code detection system is the same for both
models. This would cause the low (no) voltage indication....no sensor
to send any voltage. -- J.E. Winburn

NOTE #3

Matt Rowe <[email protected]> comments: The throttle
postion circuit is a sensor which tells the computer how far the
accelerator is depressed. So a fault in this that is intermitent is
probably due to a loose wire or connector. The Throttle Position Sensor
(TPS) is located on the throttle body on the opposite side of the
throttle cable. The connector should have a round rubber cover over the
connections. Clear the fault codes, start the car and try jiggling the
wires/connectors to try to trip a fault code. Since this sensor is the
only way the computer can tell where the throttle is so a loss of this
signal could cause the other problems so start with trying to fix this
one.

NOTE #4

During cranking, the computer will test the current through the
injector to see whether there's too much resistance in the injector's
path. If there is, code 26 is set.
In my Le Baron, the problem was cured with copious use of
television tuner
cleaner on the Bosch connector and the injector's connector.
For TBI engines, the injector's cold resistance should be between
0.9 and 1.2 ohms (specs vary with year). This is a peak-and-hold
injector. On a properly operating system with the engine idling the
peak period should be about 1.2 milliseconds whereas the hold period
will vary with parameters such as temperature, MAP reading, etc. If
it's lower than this at idle, then either the injector's shorted or
there's a defect in the injector driver circ. ()




050-559193
Gershon
[email protected]