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
Diagnostic Trouble Code Definitions
DIAGNOSTIC TROUBLE CODE DEFINITIONS
| Fault Code | Definition | ||
|---|---|---|---|
| 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 25 (1) | Ignition Misfire | ||
| 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 | ||
|
|
|||
DIAGNOSTIC TROUBLE CODE ORDER OF SYSTEM PRIORITY
| Fault Code | Definition | ||
|---|---|---|---|
| Code 02 | Reconnected ECM Fault | ||
| Code 29 | ECM Memory Fault | ||
| Code 44 | Left Bank Heated Oxygen Sensor Fault (Bank "A") | ||
| Code 45 | Right Bank Heated Oxygen Sensor Fault (Bank "B") | ||
| Code 25 (1) | Ignition Misfire | ||
| Code 40 | Left Bank Misfire Fault (Bank "A") | ||
| Code 50 | Right Bank Misfire Fault (Bank "B") | ||
| Code 12 | Mass Airflow Sensor Fault | ||
| Code 21 | Tune Select Resistor Fault | ||
| Code 34 | Left Bank Injector Fault (Bank "A") | ||
| Code 36 | Right Bank Injector Fault (Bank "B") | ||
| Code 14 | Engine Coolant 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 88 | Canister Purge Valve Leak Fault | ||
| Code 28 | Engine Air Leak Fault | ||
| Code 23 | Fuel Supply Fault | ||
| Code 48 | Idle Air Control Valve Fault | ||
| Code 68 | Vehicle Speed Sensor Input Fault | ||
| Code 69 | Park/Neutral Position Switch Fault | ||
| Code 59 | Group Faults 23/28 | ||
| Code 15 | Fuel Temperature Sensor Fault | ||
|
|
|||
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.