Here's a list of the computer codes. It is NOT a complete list
but very close to one. Any disagreements, additions, deletions,
and/or modifications will be most welcomed.
Thanks
B.T.
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 (87-89)
OR solenoid coil circuit (85-89 Turbo I-IV)
OR Trans temperature 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 (SEE NOTE
#6)
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 (SEE NOTE #5!)
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
* Activates check engine lamp on most models.
NOTE #1.
The power module has an air-cooled resistor which senses incoming air
temperature.
The logic modules uses this information to control the field current in the
alternator.
This code applies ONLY to alternators whose voltage is computer regulated.
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 manuals: the trailer towing package includes a
transmission coolant
temp sensor while the standard package doesn't. This may cause the low
(no) voltage indication. -- J.E. Winburn
NOTE #3.
Matt Rowe comments: The throttle postion circuit tells the computer how far
the accelerator
is depressed. The Throttle Position Sensor (TPS) is 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. Loss of this signal could
cause other problems.
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.
The problem may be cured with tuner cleaner on the connectors.
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. With the engine
idling the
peak period should be about 1.2 milliseconds whereas the hold period will
vary.
If it's lower than this at idle, then the injector's shorted or there's a
defect in the injector
driver circuit. (Bohdan Bodnar)
NOTE #5.
Wade Goldman wrote: In my case, the breather tube leading into the
catalytic converter had rusted
and become detached. This some how would cause the sensor to read an over
rich condition and run
crummy. I did not trust the reliability of the weld over a corroded surface
and opted for the more
expensive route of replacing the converter, breather tube and all.
NOTE #6.
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(s).
In my LeBaron, the Z1 circuit leaves the power module and splits into two
paths:
the fuel pump and the positive side of the ignition coil. Internal to the
power module
is the auto shutdown relay (in my case, it's a sealed box about 1" by 1").
The output voltage
is monitored to determine whether the relay responds correctly. I suspect
that the ASD
relay (and, therefore, the Z1 circuit) also feeds the fuel injector(s)
driver(s) and
current sensing circuit, but can't prove this.
I've used the Z1 voltage to test for good power connections to the power
module.
I connected my OTC 500 multimeter from the battery's positive post to the
ignition
coil's switched battery terminal and measured the voltage drop using the
bar graph
to monitor peak voltages. Voltage spikes of around 200 mV to 300 mV are ok --
anything more means tv tuner cleaner time (or replacing the power module).
Another thing to check is the maximum voltage drop during the priming
pulse.With the old
power module, I was losing about 2 volts across the circuit; the
replacement is losing about 1/4 volt.
(Thanks, bbodnar@lucent.com)
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