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.

1993 Land Rover Defender 110FACTORY OEM SERVICE PROCEDURE

Code 18: Throttle Position Sensor Input High/Mass Airflow Sensor Input Low Fault

Test Throttle Position (TP) sensor and Mass Airflow (MAF) sensor. Perform Test "H". See Fig 1 and Fig 2 . After completing the tests, retest the vehicle to ensure the faults have been rectified. If faults still persist, recheck using Lucas Diagnostic Equipment or Test Book.

Fig 1: Throttle Position Sensor Input High/Mass Airflow Sensor Input Low Fault Test "H" (1 Of 2)

Courtesy of LAND ROVER NORTH AMERICA, INC.

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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.