The crankshaft position sensor is an engine management component found on virtually all modern vehicles with internal combustion engines. It monitors the position and rotational speed of the crankshaft and sends the information to the engine control unit so it can make appropriate adjustments based on operating conditions. The crankshaft speed and position are some of the most important parameters used in engine management calculations, and many engines cannot run if the crankshaft position sensor is not providing an accurate signal. Usually a problematic crankshaft position sensor will produce a few symptoms that alert the driver of a potential problem that should be serviced.

1. Issues starting the vehicle

The most common symptom associated with a bad or failing crankshaft position sensor is difficulty starting the vehicle. The crankshaft position sensor monitors the position and speed of the crankshaft and other parameters that play an important role when starting the engine. If the crankshaft position sensor is having a problem, the vehicle may have intermittent starting issues or may not start at all.

2. Intermittent stalling

Another symptom commonly associated with a problematic crankshaft position sensor is intermittent stalling. If the crankshaft position sensor or its wiring have any issues, it can cause the crankshaft signal to be cut off while the engine is running, which can cause the engine to stall. This is usually a symptom of a wiring problem, however a bad crankshaft position sensor can also produce this symptom.

3. Check Engine Light comes on

Another issue of a potential problem with the crankshaft position sensor is an illuminated Check Engine Light. If the computer detects a problem with the crankshaft position sensor’s signal, it will activate the Check Engine Light to alert the driver of the problem. A Check Engine Light can also be set off by a wide variety of other issues so having computer scanned for trouble codes is highly recommended.

The crankshaft position sensor is critical to proper engine functionality and performance due to the vital signal it provides for engine calculations. When it has issues, they can quickly lead to problems that affect the drivability of the vehicle. For this reason, if you suspect that your crankshaft position sensor has an issue, have the vehicle inspected by a professional technician from YourMechanic. They will be able to diagnose your car and replace your crankshaft position sensor if necessary.

This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Crankshaft Position Sensor and was authored by Ed Ruelas.


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