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
Engine Controls - Self-Diagnostics
- Introduction
- Self-Diagnostic System
- Summary
- Diagnostic Trouble Code Definitions
- Component Locations
- Connector Identification
- Diagnostic Tests
- Notes
- 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: Group Fault Codes 23/28
- Code 68: Road Speed Sensor
- Code 69: Gear Switch
- Code 88: Purge Valve Leak
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.