Fault analysis of crankshaft position sensor for damage reason

Date:Nov 04, 2020

The crankshaft position sensor plays a very important role in the engine. The crankshaft position sensor can detect the crankshaft Angle and piston top stop, and send the detected signal to the engine computer to control the ignition time and fuel injection timing. In addition, the crankshaft position sensor can also measure the engine speed.


There are three main types of crankshaft position sensors, namely magnetoelectric induction, Hall effect and photoelectric type. Crankshaft position sensor failure, due to its different types, there are different reasons.

1. Magnetoelectric induction

Advantages: simple structure, strong durability, high temperature resistance, assembly requirements are not high.

Disadvantages: The signal is easy to be interfered, ECU needs to design the relevant signal processing circuit, the accuracy is low, not suitable for VVT engine.

The fault of the magnetoelectric induction crankshaft position sensor is that the engine cannot start. When checking the condition of the engine, it is found that the late ignition is the real reason for the engine not to start.

Solution: Reconnect the circuit, readjust the distributor, and check the ignition timing.

2. Hall effect

Advantages: the output is digital signal, high precision.

Disadvantages: high requirements for assembly, rotary sensitive installation, and integration of electrical components, EMC requirements.

Hall effect crankshaft position sensor is used to control the sequential injection, ignition time and detonation of the engine. In case of failure, the transmission signal is out of the normal range.

Solution: Check permanent magnet, magnetic plate and integrated circuit for normal operation.

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