Crankshaft position sensor malfunctions and solutions
2026-07-17
If the crankshaft position sensor is damaged, the engine control unit (ECU) will not receive a reference signal during startup, and the ignition coil will not generate high voltage. If the engine does not start within 2 seconds of turning on the ignition switch, the ECU will cut off the control voltage to the fuel pump relay, stopping power supply to the fuel pump and ignition coil, preventing the vehicle from starting. Crankshaft position sensor malfunction and solutions?
Magnetic-electric induction type
Advantages: Simple structure, robust and durable, high temperature resistance, low assembly requirements.
Disadvantages: The signal is susceptible to interference; the ECU needs to design related signal processing circuits; lower accuracy; not suitable for engines with WT (Toyota Wing) control.
A malfunction of a magnetic-electric induction type crankshaft position sensor results in the engine failing to start. Upon checking the engine condition, it was found that late ignition was the real cause of the engine starting failure.
Solution: Reconnect the wiring, readjust the distributor, and check the ignition timing.
Hall effect type
Advantages: Digital output signal, high accuracy.
Disadvantages: High assembly requirements, rotationally sensitive installation, and integrated electrical components, subject to EMC requirements.
Hall effect crankshaft position sensors are used for sequential fuel injection, ignition timing, and knock control in the engine. A malfunction occurs when the transmitted signal is outside the normal range.
Solution: Check the permanent magnet, magnetic plate, and integrated circuit for proper function.
Photoelectric type
A malfunction of a photoelectric crankshaft sensor results in poor engine acceleration, automatic engine stalling during startup, and sometimes high-voltage sparks. The cause is a malfunctioning ignition system, resulting in a weak high-voltage spark.
Solution: Check the low-voltage circuit, main relay, internal short circuit in the high-voltage ignition coil, faults in the engine control unit, and abnormal wear of some mechanical components.
Magnetic-electric induction type
Advantages: Simple structure, robust and durable, high temperature resistance, low assembly requirements.
Disadvantages: The signal is susceptible to interference; the ECU needs to design related signal processing circuits; lower accuracy; not suitable for engines with WT (Toyota Wing) control.
A malfunction of a magnetic-electric induction type crankshaft position sensor results in the engine failing to start. Upon checking the engine condition, it was found that late ignition was the real cause of the engine starting failure.
Solution: Reconnect the wiring, readjust the distributor, and check the ignition timing.
Hall effect type
Advantages: Digital output signal, high accuracy.
Disadvantages: High assembly requirements, rotationally sensitive installation, and integrated electrical components, subject to EMC requirements.
Hall effect crankshaft position sensors are used for sequential fuel injection, ignition timing, and knock control in the engine. A malfunction occurs when the transmitted signal is outside the normal range.
Solution: Check the permanent magnet, magnetic plate, and integrated circuit for proper function.
Photoelectric type
A malfunction of a photoelectric crankshaft sensor results in poor engine acceleration, automatic engine stalling during startup, and sometimes high-voltage sparks. The cause is a malfunctioning ignition system, resulting in a weak high-voltage spark.
Solution: Check the low-voltage circuit, main relay, internal short circuit in the high-voltage ignition coil, faults in the engine control unit, and abnormal wear of some mechanical components.
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