1991-1995 Jeep Cherokee XJ OBD-I Diagnostic Trouble Codes [PDF]

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OBD-I Diagnostic Trouble Codes



On OBD-I vehicles, Diagnostic Trouble Codes (DTC's) can be displayed by cycling the key ON-OFFON-OFF-ON without starting the engine, and watching the Check Engine Light (CEL) for flashing. Count the flashes. An example would be "FLASH-pause-FLASH-pause-FLASH - long pause - FLASH-pauseFLASH" for DTC 32. There will be an even longer pause in between codes, and all you need to do to display them again is cycle the key ON-OFF-ON-OFF-ON again. This only applies to 1991-1995 vehicles. Jeep vehicles were "pre-OBD" from 1990 back, and were "OBD-II" from 1996 forward. Codes displayed with a RED background will cause the CEL to light ("Check Engine" - a request for action) and those with a GREEN background do not (and therefore will be "dormant" and not give you any alert at all, until you cycle the key. With that in mind, it's probably not a bad idea to cycle the key about every other month, just to make sure there aren't any latent codes that aren't illuminating the CEL. One thing - these codes are taken from the 1991 & 1994 FSMs. The rest of the OBD-I codes should be similar - if you have a source that says differently, please send me a copy so I can update this reference. Code



Meaning



Explanation



CEL?



11



No Ignition/Crank Reference No ignition (CPS) reference signal detected during Signal engine cranking



No



12



Battery Disconnect



Direct Battery Input to Powertrain Control Module (PCM) disconnected in last 50 key-ON cycles



No



13



Slow change in Idle MAP signal



No variation in MAP sensor signal detected



Yes



13



No change in MAP from "Start" to "Run"



No difference is recognized between the engine MAP reading and barometric pressure reading at engine startup



Yes



14



MAP Sensor Voltage Input too High/Low



Manifold Absolute Pressure sensor input voltage outside acceptable range



Yes



15



No Vehicle Speed Sensor Reading



No distance speed/sensor signal detected during road load conditions



CA Only



7/1/2011 3:30 PM



Engine Coolant Temperature remains below normal operating temperatures during vehicle travel



17



Engine is "Cold" too long



No



21



HEGO Sensor Signal stays at Neither "Rich" nor "Lean" condition detected by Heated centre Exhuast Gas Oxygen (HEGO) Sensor



CA Only



21



HEGO Sensor Signal shorted HEGO Sensor Input voltage maintained above normal to voltage operating range



CA Only



22



CTS Voltage too High/Low



Coolant Temperature Sensor input voltage outside of acceptable range



Yes



23



Air Charge Temperature Sensor Voltage too High/Low



Manifold Air Temperature (MAT) sensor input voltage outside acceptable range



Yes



24



TPS Voltage too High/Low



Throttle Position Sensor (TPS) input voltage outside acceptable range



Yes



25



Automatic Idle Speed Motor An "open" or "shorted" condition detected in one or Circuits more of the Idle Air Control (IAC) motor circuits



CA Only



27



Injector Control Circuit



Injector Output Driver does not respond properly to control signal



Yes



33



ACC Relay Circuit



An "open" or "short" circuit detected in the Air Conditioning Clutch Relay control circuit



No



34 (XJ/MJ Speed Control Solenoid Only) Circuits



An "open" or "short" condition detected in the Air Conditioning Clutch Relay control circuit



No



35 (XJ/MJ Radiator Fan Relay Only)



An "open" or "short" circuit detected in the electric radiator cooling fan relay control circuit



No



41



Alternator Field not switching properly



Alternator field is not switching properly in response to PCM regulator signal



Yes



42



ASD Relay Circuit



An "open" or "short" circuit detected in the Auto ShutDown (ASD) Relay control circuit, or no ASD voltage sensed at SBEC/PCM



No



44



Battery Temperature Sensor Battery Temperature Sensor input voltage out of Voltage out of limits operational limits



No



46



Charging System Voltage too Charging System Voltage exceeds operational limits high



Yes



47



Charging System Voltage too Charging System Voltage below operational limits low



Yes



51



HEGO Sensor Signal Stays "below centre"



HEGO Sensor indicates constant "Lean AFR" condition



CA Only



52



HEGO Sensor Signal stays "above centre"



HEGO Sensor indicates constant "Rich AFR" condition



CA Only



53



Internal PCM/SBEC Failure



Internal failure of Powertrain Control Module/Single Board Engine Controller module



No



53



PCM/SBEC Failure/SPI Communications



No internal communication between co-processors



No



Kelley's Works in Progress



http://www.kelleyswip.com/obd1.html



54



No SYNC pickup signal



No SYNC pickup signal from distributor sensor (Camshaft Position Sensor)



No



62



Controller Failure/EMR Miles Not Stored



Controller Failure - EMR Miles not stored/writted to EEPROM



No



63



Controller Failure EEPROM Write Denied



Attempt to write/store data to controller EEPROM was denied/unsuccessful.



No



An "open" or "shorted" condition detected in the fuel pump ballast resistor bypass circuit



No



76 (XJ/MJ Fuel Pump Ballast Bypass Only) Relay Circuit 55



Display Finished



Indicated display of DTC's is finished



N/A