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.
1994 Land Rover Defender 90FACTORY OEM SERVICE PROCEDURE
Engine Performance Self-Diagnostics
- Introduction
- Self-Diagnostic System
- Summary
- Diagnostic Trouble Code Definitions
- Component Locations
- Connector Identification
- Diagnostic Tests
- Notes
- Check Engine Warning Light Inoperative
- Engine Control Module Power & Ground Test
- No Diagnostic Trouble Code Test
- Code 02: Reconnected ECM Fault
- Code 12: Mass Airflow Sensor Fault
- Code 14: Engine Coolant Temperature Sensor Fault
- Code 15: Fuel Temperature Sensor Fault
- Code 17: Throttle Position Sensor Fault
- Code 18: Throttle Position Sensor Input High/Mass Airflow Sensor Input Low Fault
- Code 19: Throttle Position Sensor Input Low/Mass Airflow Sensor Input High Fault
- Code 21: Tune Select Resistor Fault
- Code 23: Fuel Supply Fault
- Code 28: Engine Air Leak Fault
- Code 29: ECM Memory Fault
- Code 34: Left Bank Injector Fault (Bank "A")
- Code 36: Right Bank Injector Fault (Bank "B")
- Code 40: Left Bank Misfire Fault (Bank "A")
- Code 44: Left Bank Heated Oxygen Sensor Fault (Bank "A")
- Code 45: Right Bank Heated Oxygen Sensor Fault (Bank "B")
- Code 48: Idle Air Control Valve Fault
- Code 50: Right Bank Misfire Fault (Bank "B")
- Code 59: Group Faults 23/28
- Code 68: Vehicle Speed Sensor Input Fault
- Code 69: Park/Neutral Position Switch Fault
- Code 88: Canister Purge Valve Leak Fault
- Wiring Diagrams
Factory Service Tools
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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.
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