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.
1990 Land Rover Range Rover BaseFACTORY OEM SERVICE PROCEDURE
Diagnostic Trouble Code Definitions
DIAGNOSTIC TROUBLE CODE DEFINITIONS
| Fault Code | Definition | ||
|---|---|---|---|
| Code 02 | Reconnected Engine Control Module | ||
| Code 12 | Mass Airflow Sensor | ||
| Code 14 | Coolant Temperature Sensor | ||
| Code 15 | Fuel Temperature Sensor | ||
| Code 17 | Throttle Position Sensor | ||
| Code 18 | Throttle Position Sensor Input High/Mass Airflow Sensor Low | ||
| Code 19 | Throttle Position Sensor Input Low/Mass Airflow Sensor High | ||
| Code 21 | Tune Select Resistor | ||
| Code 23 | Fuel Supply | ||
| Code 25 | Misfire (Non Specific) | ||
| Code 28 | Air Leak | ||
| Code 29 | Engine Control Module Memory Check | ||
| Code 34 | Injector - Bank "A" (Left Bank) | ||
| Code 36 | Injector - Bank "B" (Right Bank) | ||
| Code 40 | Misfire - Bank "A" (Left Bank) | ||
| Code 44 | Heated Oxygen Sensor - Bank "A" (Left Bank) | ||
| Code 45 | Heated Oxygen Sensor - Bank "B" (Right Bank) | ||
| Code 48 | Air By-Pass Valve | ||
| Code 50 | Misfire - Bank "B" (Right Bank) | ||
| Code 59 (1) | Group Fault Codes 23/28 | ||
| Code 68 | Road Speed Sensor | ||
| Code 69 | Gear Switch | ||
| Code 88 | Purge Valve Leak | ||
|
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DIAGNOSTIC TROUBLE CODE ORDER OF SYSTEM PRIORITY
| Fault Code | Definition | |
|---|---|---|
| Code 02 | Reconnected Engine Control Module | |
| Code 29 | Engine Control Module Memory Check | |
| Code 44 | Heated Oxygen Sensor - Bank "A" (Left Bank) | |
| Code 45 | Heated Oxygen Sensor - Bank "B" (Right Bank) | |
| Code 25 | Misfire (Non Specific) | |
| Code 40 | Misfire - Bank "A" (Left Bank) | |
| Code 50 | Misfire - Bank "B" (Right Bank) | |
| Code 12 | Mass Airflow Sensor | |
| Code 21 | Tune Select Resistor | |
| Code 34 | Injector - Bank "A" (Left Bank) | |
| Code 36 | Injector - Bank "B" (Right Bank) | |
| Code 14 | Coolant Temperature Sensor | |
| Code 17 | Throttle Position Sensor | |
| Code 18 | Throttle Position Sensor Input High/Mass Airflow Sensor Low | |
| Code 19 | Throttle Position Sensor Input Low/Mass Airflow Sensor High | |
| Code 88 | Purge Valve Leak | |
| Code 28 | Air Leak | |
| Code 23 | Fuel Supply | |
| Code 48 | Air By-Pass Valve | |
| Code 68 | Road Speed Sensor | |
| Code 69 | Gear Switch | |
| Code 59 (1) | Group Fault Codes 23/28 | |
| Code 15 | Fuel Temperature Sensor | |
|
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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