This tutorial is also available in French ➔

Crankshaft sensor change on Defender Td5

Vehicle ➔ Defender 110 Td5 2002

Difficulty ➔ Easy

Time ➔ 1 hour

Summary

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Fit the air inlet duct

Recommendations

This tutorial concerns only the Defender Td5.

What is the role of the crankshaft sensor ?
• When the engine is running, the crankshaft sensor continuously detects the presence or absence of holes on the circumference of the flywheel.
• The crankshaft sensor communicates this information to the ECU (Engine Control Unit).
• Thanks to this information, the ECU knows perfectly the position of each of the 5 pistons. It can thus control the fuel injection in each of the cylinders.
• In addition, if the Defender was equipped with a rev counter, it is the crankshaft sensor that would give it the information of the engine speed.

What are the symptoms of a faulty crankshaft sensor ?
• Generally, when the crankshaft sensor is faulty, the engine simply refuses to start.
• As the ECU does not receive any information on the position of the pistons, it does not trigger the fuel injection into the cylinders.
• The starter motor turns the engine, the engine refuses to start and there is no emission at the exhaust.

Before changing the crankshaft sensor, start by checking the condition of the wiring harness. It frequently happens that a wire is cut at the connector.

Wiring harness crankshaft sensor connector Defender Td5

Sometimes the crankshaft sensor and its harness become saturated with oil. This causes micro-cuts in the injection and the engine misfires. In this case, simply clean the connectors with contact cleaner.

On the Defender Td5, the crankshaft sensor is sometimes mounted with a spacer (this is not the case on our Defender). This spacer separates the sensor by a few millimeters from the flywheel. If you see this spacer during disassembly, retrieve it to fit it back during reassembly.

Required Tools