PCM Fault Codes

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OBDI Ram Gasoline Engine PCM Fault Codes

OBD1 DTC's for 1994-1997 Rams with Gas Engines

When the engine is started, the check engine light should illuminate for 3 seconds as a bulb test. If the light illuminates at any other time, a fault has been detected. Not all fault codes are stored in memory.

The dealer can read fault codes with the DRB series diagnostic tool.
98+ Rams do not flash the codes, but on 94-97 Rams, the owner can read the codes this way:

Turn the engine off, then turn the key ON, OFF, ON, OFF, ON without starting the engine.

The codes will begin to flash on the Check Engine light. The light will blink the number of the first digit, pause, and blink the number of the second digit.

All codes are 2 digit numbers.

The code 55 indicates the end of the messages.

As an example, a stored code of 23 would flash 2 times, pause, flash 3 times, pause, flash 5 times, pause, and flash 5 times.

Certain conditions must exist for a fault code to be stored. Many codes require specific engine speeds, temperatures, or voltages to set and store a code. Many components may interact to to unbalance the emission control system and set seemingly unrelated fault codes. When any emissions related fault is detected, all electrical connectors and vacuum and fuel hoses should be inspected for proper connection, abrasion, etc.

If any problem is repaired or ceases to exist, the fault code stored in the PCM will be erased after 51 engine starts. All stored codes will be erased if the battery is disconnected for 15 minutes, but a fault code 12 will be set when the battery is reconnected..

Diagnostic Trouble Code Descriptions and service hints.
Fault Code	DRB Display	Code Description. Service hints.
11	No Crank reference signal at PCM	No Distributor reference signal detected during engine cranking. Check the circuit between the distributor and PCM.
12	Battery Disconnect	Direct Battery input to PCM disconnected within last 50 ignition key-on cycles. Normal if battery has been disconnected, otherwise check battery power and ground connections.
13**	No change in MAP from start to run	No difference seen between the engine MAP reading and the barometric (atmospheric) pressure reading at startup. Indicates a problem with the MAP sensor vacuum system.
14**	MAP sensor voltage too low or too high	MAP sensor voltage output is outside the acceptable range.
15**	No Vehicle speed sensor signal	No signal received from the vehicle speed sensor during road load operation.
17*	Engine is cold too long	Engine temperature too high or too low while traveling. Check coolant level, radiator cap, temperature sensor, and thermostat.
21**	O2S Stays at center O2S shorted to voltage	O2 sensor does not detect rich or lean condition, or O2 sensor input voltage too high. DRB will indicate which side with dual sensors. The O2 sensor signal should fluctuate under normal conditions.
22**	ECT sensor voltage too high or too low	Engine Coolant temperature sensor input out of normal range. Check engine temperature sensor.
23**	Intake air temp sensor voltage too high or low	Intake air manifold temperature sensor is out of range. Check sensor.
24**	Throttle position sensor voltage too high or low	TPS sensor is out of normal range.
25**	Idle air control motor circuits	A short is detected in one or more of the idle air motor circuits.
27*	Injector # control circuit	Injector number # output driver circuit does not respond to the control signal. Check the affected circuit.
31**	EVAP Solenoid Circuit	Short or open in the EVAP solenoid circuit. Check for loose, broken, or shorted wire in the charcoal canister purge solenoid wiring and connectors.
32**	EGR Solenoid circuit	Short or open in the EGR solenoid circuit. Check for loose, broken, or shorted wire in the EGR valve wiring and connectors. Possible air fuel ratio imbalance not detected during diagnosis.
33*	AC clutch relay circuit	Short or open in the AC clutch circuit.
34*	Speed control circuit or speed control switch always low or high	An open or short in the speed control vacuum or vent circuits. Speed control switch input above or below normal range.
35	Radiator Fan low speed relay circuit	Open or short in the radiator fan relay wiring.
37**	Torque converter clutch solenoid CKT or Trans temp sensor too high or low	Open or short in CKT wiring or connectors. Voltage out of range at transmission temperature sensor input. See NOTE #1 below
41**	Generator field not switching properly	Open or short in the generator (alternator) field control (regulator) circuit. This indicates a problem with the charging circuit and the fault is set when the battery voltage from the ASD relay falls below 11.75 volts. Wiring, connectors, fuses, and the ASD relay should be checked. A shorted battery cell can also trigger this fault.
42*	Auto shutdown relay circuit	Open or short in the ASD relay wiring or connectors.
43**	Ignition coil circuit #	Open or short in number # coil circuit. Indicates that the ignition coil's peak primary circuit current is not achieved with the maximum dwell time.
44*	Battery temp sensor volts out of range	An open or short in the engine coolant temperature sensor circuit or a problem in the PCM's battery temperature circuit.
45*	Trans OD solenoid circuit	Transmission OD solenoid circuit failure. Open or short in the transmission overdrive solenoid circuit.
46**	Charging system voltage too high	Battery voltage sense input above target charging voltage during engine operation. Computer is indicating that the battery voltage is not being regulated.
47**	Charging system voltage too low	Battery voltage sense input above target charging voltage during engine operation. Also, no significant change in battery voltage was detected during a test of the generator output.
51**	System lean L-Idle Adap at rich limit or lean R-Idle Adap at rich limit	O2 sensor signal indicates lean air/fuel ratio during engine operation. The computer ran the mixture to the rich limit of programming, but the O2 sensor still indicated a lean condition. L or R indicate left or right side O2 sensor. Fuel pressure problems can lean the mixture and set this fault.
52**	System rich L-Idle Adap at lean limit or rich R-Idle Adap at lean limit	O2 sensor signal indicates rich air/fuel ratio during engine operation. The computer ran the mixture to the lean limit of programming, but the O2 sensor still indicated a rich condition. L or R indicate left or right side O2 sensor. Faulty ignition components, high or low fuel pressure, or leaking injectors can set this fault.
53*	Internal PCM failure or PCM SPI comm failure	An internal PCM failure or PCM communications failure has been detected.
54*	No cam sync signal at PCM	No fuel sync (camshaft signal) detected during engine crank. No camshaft position sensor signal was received from the distributor. Problem with the distributor synchronization circuit.
55	N/A	End of message code. A DTC 55 is used to end all DTC messages. This code does not show on the DRB tool and indicates a completion of the stored codes on the Malfunction Indicator Lamp (check engine lamp).
62*	PCM failure SRI miles not stored	Unsuccessful attempt to update Service Reminder Indicator miles in the PCM EEPROM (memory).
63*	PCM Failure EEPROM write denied	Unsuccessful attempt to write and EEPROM location by the PCM. Controller failure, check the PCM. This code can be set when attempting an unauthorized reprogram of the PCM.
71**	Aux 5V signal voltage low	The auxiliary 5 volt supply output voltage is low. The 5 volt output signal is not reaching the required voltage level.
72**	Catalytic Converter efficiency failure	The catalytic converter is not converting emissions in the proper ratio.

Fault codes with * = Check engine lamp may not illuminate at all times if this code was recorded.
Fault codes with ** = Check engine lamp will illuminate when the engine is running if this code was recorded.
Fault codes with red stars * or ** vary from above, depending on the model year.

NOTE #1 - From the 1995 TRUCK (Ram) manuals: the trailer towing package includes a transmission coolant temp sensor while the standard package doesn't. The fault code detection system is probably the same for both models. This could cause the low (no) voltage indication....no sensor to send any voltage.

Other Lists of Chrysler Computer (PCM) Fault Codes

http://misterfixit.com/moparcod.htm

http://www.allpar.com/fix/codes.html

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This page was edited on: May 3, 2004