Understanding your Jeep Grand Cherokee’s On-Board Diagnostics (OBD2) codes is crucial for diagnosing and fixing issues. This guide provides a comprehensive list of OBD2 codes for 1998 Jeep Grand Cherokee models, categorized by engine type.
OBD2 Codes for 1998 Jeep Grand Cherokee: Carbureted Engines
These codes apply specifically to carbureted 1998 Jeep Grand Cherokee models:
- Code 12: No distributor reference pulses to the ECM. This is normal with the ignition on and engine off.
- Code 13: Oxygen sensor circuit issue. Requires 5 minutes of part-throttle operation under load to set.
- Code 14: Short in the coolant sensor circuit. Requires 5 minutes of operation to set.
- Code 15: Open coolant sensor circuit. Requires 5 minutes of operation to set.
- Code 21: Throttle position sensor circuit issue. Requires 25 seconds at curb idle to set.
- Code 23: Mixture control solenoid circuit short or open.
- Code 34: Vacuum sensor circuit issue. Requires 5 minutes at curb idle to set.
- Code 41: No distributor reference pulses at specific manifold vacuum. This code is stored in memory.
- Code 42: Electronic Spark Timing (EST) circuit short to ground or open circuit.
- Code 44: Lean exhaust indication. Requires 5 minutes in closed loop, part-throttle operation.
- Code 45: Rich exhaust indication. Requires 5 minutes in closed loop, part-throttle operation. Codes 44 and 45 together indicate an oxygen sensor problem.
- Code 51: Faulty PROM (calibration unit) or installation. Takes 30 seconds to set.
- Code 54: Mixture Control (MC) solenoid circuit short or faulty ECM.
- Code 55: Voltage reference short to ground (terminal 21), faulty oxygen sensor, or faulty ECM.
OBD2 Codes for 1998 Jeep Grand Cherokee: Fuel Injected Engines (Except 1991 and Later)
These codes are for fuel-injected models, excluding those from 1991 onwards:
- Code 1000-1073: These codes cover a range of issues from ignition line problems and low battery voltage to sensor ground issues and A/C system malfunctions. Refer to a repair manual for specific details on each code.
- Code 1200-1223: These codes indicate more serious issues like a defective ECU, shorted injectors, and lack of voltage at critical components.
OBD2 Codes for 1998 Jeep Grand Cherokee: Fuel Injected Engines (1991-1995 Models)
For 1991-1995 fuel-injected models:
- Code 11-88: These codes encompass a wide variety of problems related to engine components and systems, including camshaft signals, MAP sensors, vehicle speed sensors, and more. Consult a service manual for detailed information on each code. “Code 88” indicates the start and end of the test.
OBD2 Codes for 1998 Jeep Grand Cherokee: Fuel Injected Engines (1996 and Later Models)
These codes apply to 1996 and later fuel-injected models and utilize the standardized P-code format:
- P0107-P1899: These codes cover a broad spectrum of potential problems, ranging from sensor malfunctions (e.g., manifold absolute pressure, intake air temperature) to issues with the catalytic converter, evaporative emissions system, fuel system, and transmission. A detailed repair manual should be consulted for in-depth information on each specific code.
Using OBD2 Codes for Diagnostics
This list serves as a starting point for troubleshooting. While these codes offer valuable clues, further diagnostic steps are often necessary to pinpoint the exact cause of a problem. Consult a factory service manual for your specific 1998 Jeep Grand Cherokee model for detailed troubleshooting procedures and repair information. Always prioritize safety when working on your vehicle.
