Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSJEEP1991CHEROKEE 2WD L4-150 2.5L VIN P MFIREPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONDIAGNOSTIC TROUBLE CODE DESCRIPTIONS2 AND 3 DIGIT CODES
1991 Jeep Cherokee 2WD L4-150 2.5L VIN P MFI
2 and 3 Digit Codes
1991 Jeep Cherokee 2WD L4-150 2.5L VIN P MFISECTION 2 and 3 Digit Codes
NOTE: The following chart is provided to accommodate users who do not have the proper scan tool available. It should be noted, however, that in order to properly diagnose and repair these vehicles, the proper scan tool should be used. To receive the appropriate diagnostic chart for your specific trouble code, refer to FAULT MESSAGE TO DIAGNOSTIC CHART CONVERSION.
FAULT CODE NO. DRB II DISPLAY DESCRIPTION OF FAULT CONDITION
11 IGN reference signal No distributor reference signal detected during engine cranking.
12 No. of key-ons since last Direct battery input to controller disconnected with the last 50
fault ignition key-on cycles.
13 MAP pneumatic signal No variation in MAP sensor signal is detected.
or
MAP pneumatic change No difference is recognized between the engine MAP reading and the stored barometric pressure reading.
14 MAP voltage too low MAP sensor input below minimum acceptable voltage.
or
MAP voltage too high MAP sensor input above maximum acceptable voltage.
15 Vehicle speed signal No distance sensor signal detected during road load conditions.
16 Battery input sense Battery voltage sense input not detected during engine running.
17 Low engine temp Engine coolant temperature remains below normal operating temperatures during vehicle travel.
21 Oxygen sensor signal Neither rich nor lean condition is detected from the oxygen
or sensor input.
02 sensor shorted high Oxygen sensor input voltage maintained above normal operating range.
22 Coolant voltage low Coolant temperature sensor input below the maximum acceptable
or voltage.
Coolant voltage high Coolant temperature sensor input above the maximum acceptable voltage.
23 Charge Temp/MAT sensor MAT sensor input voltage below the
voltage low minimum acceptable standard.
24 TPS voltage low Throttle position sensor input below the minimum acceptable
or voltage.
TPS voltage high Throttle position sensor input above the maximum acceptable voltage.
25 AIS motor circuits A shorted condition detected in one or more of the AIS control circuits.
26 INJ 1 peak current High resistance condition detected in the INJ 1 injector bank
or circuit.
INJ 2 peak current High resistance condition detected in the INJ 2 injector bank
or circuit.
INJ 3 peak current High resistance condition detected in the INJ 3 injector bank circuit.
27 INJ 1 control circuit Injector 1 output driver does not respond properly to the
or control signal.
INJ 2 control circuit Injector 2 output driver does not respond properly to the
or control signal.
INJ 3 control circuit Injector 3 output driver does not respond properly to the control signal.
31 Purge solenoid circuit An open or shorted condition detected in the purge solenoid circuit.
32 EGR solenoid circuit An open or shorted condition detected in the EGR solenoid
or circuit.
EGR system failure Required change in fuel/air ratio not detected during diagnostic test. (California emissions packages only.)
33 A/C clutch relay circuit An open or shorted condition detected in the A/C clutch relay circuit.
34 S/C solenoid circuits An open or shorted condition detected in the speed control vacuum or vent solenoid circuits.
35 Radiator fan relay An open or shorted condition detected in the radiator fan relay circuit.
36 Wastegate solenoid circuit An open or shorted condition detected in the wastegate solenoid circuit.
37 PTU solenoid circuit An open or shorted condition detected in the torque converter part throttle unlock solenoid circuit. (Auto transmission only.)
41 Alternator field circuit An open or shorted condition detected in the alternator field control circuit.
42 ASD relay control circuit An open or shorted condition detected in the auto shut down relay circuit.
43 Ignition coil control Peak primary circuit current not achieved with maximum dwell
circuit time.
44 Battery Temp. sensor Battery Temperature sensor out of limit.
out of limit
45 Overdrive solenoid An open or shorted condition detected in the overdrive solenoid circuit. (Auto trans only.)
46 Battery voltage high Battery voltage sense input above target charging voltage during engine operation.
47 Battery voltage low Battery voltage sense input below target charging voltage during engine operation.
51 Lean F/A condition Oxygen sensor signal input indicates lean fuel/air ratio condition during engine operation.
52 Rich F/A condition Oxygen sensor signal input indicates rich fuel/air ratio condition
or during engine operation.
Excessive leaning Adaptive fuel value leaned excessively due to a sustained rich condition.
53 Internal controller failure Internal engine controller fault condition detected.
or
Controller failure SPI No internal communication between coprocessors.
communications
54 No sync pick up signal No fuel sync signal detected during engine rotation.
55 N/A Completion of fault code display on check engine lamp.
62 EMR mileage accum Unsuccessful attempt to update EMR mileage in the controller EEPROM.
63 EEPROM write denied Unsuccessful attempt to write to an EEPROM location by the controller.
76 Fuel Pump Resistor Bypass An open or shorted condition detected in
Relay Circuit the ballast resistor bypass circuit.
FAULT CODE NO. DRB II DISPLAY DESCRIPTION OF FAULT CONDITION
11 IGN reference signal No distributor reference signal detected during engine cranking.
12 No. of key-ons since last Direct battery input to controller disconnected with the last 50
fault ignition key-on cycles.
13 MAP pneumatic signal No variation in MAP sensor signal is detected.
or
MAP pneumatic change No difference is recognized between the engine MAP reading and the stored barometric pressure reading.
14 MAP voltage too low MAP sensor input below minimum acceptable voltage.
or
MAP voltage too high MAP sensor input above maximum acceptable voltage.
15 Vehicle speed signal No distance sensor signal detected during road load conditions.
16 Battery input sense Battery voltage sense input not detected during engine running.
17 Low engine temp Engine coolant temperature remains below normal operating temperatures during vehicle travel.
21 Oxygen sensor signal Neither rich nor lean condition is detected from the oxygen
or sensor input.
02 sensor shorted high Oxygen sensor input voltage maintained above normal operating range.
22 Coolant voltage low Coolant temperature sensor input below the maximum acceptable
or voltage.
Coolant voltage high Coolant temperature sensor input above the maximum acceptable voltage.
23 Charge Temp/MAT sensor MAT sensor input voltage below the
voltage low minimum acceptable standard.
24 TPS voltage low Throttle position sensor input below the minimum acceptable
or voltage.
TPS voltage high Throttle position sensor input above the maximum acceptable voltage.
25 AIS motor circuits A shorted condition detected in one or more of the AIS control circuits.
26 INJ 1 peak current High resistance condition detected in the INJ 1 injector bank
or circuit.
INJ 2 peak current High resistance condition detected in the INJ 2 injector bank
or circuit.
INJ 3 peak current High resistance condition detected in the INJ 3 injector bank circuit.
27 INJ 1 control circuit Injector 1 output driver does not respond properly to the
or control signal.
INJ 2 control circuit Injector 2 output driver does not respond properly to the
or control signal.
INJ 3 control circuit Injector 3 output driver does not respond properly to the control signal.
31 Purge solenoid circuit An open or shorted condition detected in the purge solenoid circuit.
32 EGR solenoid circuit An open or shorted condition detected in the EGR solenoid
or circuit.
EGR system failure Required change in fuel/air ratio not detected during diagnostic test. (California emissions packages only.)
33 A/C clutch relay circuit An open or shorted condition detected in the A/C clutch relay circuit.
34 S/C solenoid circuits An open or shorted condition detected in the speed control vacuum or vent solenoid circuits.
35 Radiator fan relay An open or shorted condition detected in the radiator fan relay circuit.
36 Wastegate solenoid circuit An open or shorted condition detected in the wastegate solenoid circuit.
37 PTU solenoid circuit An open or shorted condition detected in the torque converter part throttle unlock solenoid circuit. (Auto transmission only.)
41 Alternator field circuit An open or shorted condition detected in the alternator field control circuit.
42 ASD relay control circuit An open or shorted condition detected in the auto shut down relay circuit.
43 Ignition coil control Peak primary circuit current not achieved with maximum dwell
circuit time.
44 Battery Temp. sensor Battery Temperature sensor out of limit.
out of limit
45 Overdrive solenoid An open or shorted condition detected in the overdrive solenoid circuit. (Auto trans only.)
46 Battery voltage high Battery voltage sense input above target charging voltage during engine operation.
47 Battery voltage low Battery voltage sense input below target charging voltage during engine operation.
51 Lean F/A condition Oxygen sensor signal input indicates lean fuel/air ratio condition during engine operation.
52 Rich F/A condition Oxygen sensor signal input indicates rich fuel/air ratio condition
or during engine operation.
Excessive leaning Adaptive fuel value leaned excessively due to a sustained rich condition.
53 Internal controller failure Internal engine controller fault condition detected.
or
Controller failure SPI No internal communication between coprocessors.
communications
54 No sync pick up signal No fuel sync signal detected during engine rotation.
55 N/A Completion of fault code display on check engine lamp.
62 EMR mileage accum Unsuccessful attempt to update EMR mileage in the controller EEPROM.
63 EEPROM write denied Unsuccessful attempt to write to an EEPROM location by the controller.
76 Fuel Pump Resistor Bypass An open or shorted condition detected in
Relay Circuit the ballast resistor bypass circuit.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.