What is a crankshaft position sensor?
The crankshaft position sensor is located near the engine's crankshaft, and relays information about the crankshaft’s position as it rotates.
How does the crankshaft position sensor work?
As the crankshaft spins, the position sensor magnetically reads its position. This information is constantly sent to the engine's computer for comparison with data from the camshaft position sensor.
When the two signals reach the computer, they must match; otherwise, the computer will think there is a mechanical error in the engine and will adjust some settings in response.
Several symptoms may occur when a crankshaft position sensor is failing or has failed. These symptoms can include:
Check Engine Light will illuminate
Engine will crank over but not start
Engine may stall while driving
Poor engine performance (hesitating, misfiring, and lack of power)
What are the symptoms related to a bad crankshaft position sensor?
When the computer senses the engine is out of time, it will turn on the check engine light, and the engine may start and stall, or fail to start at all. If the engine runs, it will run poorly, and get bad fuel mileage.
» LEARN MORE: Symptoms of a bad crankshaft position sensorCan I drive with a crankshaft position sensor problem?
Driving a vehicle with a failed camshaft or crankshaft position sensor is usually impossible. If driving is possible, it is not recommended. If the sensor is functioning normally and reporting an error, the engine may be out of time or may have suffered a mechanical failure.
How often do crankshaft position sensors need to be replaced?
There's no set replacement interval for the crankshaft position sensor, and on many cars, the part will last the lifetime of the vehicle. It's not uncommon for it to fail, however, and the likelihood increases once you pass 100,000 miles.
How are crankshaft position sensor issues diagnosed?
Using a professional-grade scanner, a mechanic can read where the sensors think the crankshaft and camshaft are, and compare this to their actual position. If the reading from either sensor is incorrect, the sensor will be tested and replaced if necessary.
Common misdiagnoses
A Crankshaft Position Sensor code isn't always triggered by a defective Crankshaft Sensor. It can be triggered by other worn components such as a worn timing belt or timing chain, defective ignition components, or a defective mass air flow sensor.
How is a crankshaft position sensor replaced?
To replace the crankshaft position sensor, you have to disconnect any electrical connectors and then unscrew the sensor. Sealant may be applied before inserting the new sensor into the engine.
On some vehicles, the crankshaft position sensor is located inside the engine block, and significant deconstruction is required to get to it. In these cases, we recommend trusting a professional technician with the repair.
Before replacing the crankshaft position sensor, a technician should verify that the timing chain/timing belt is in good condition and properly installed, the electrical circuit for the sensor is okay, and address any oil that is leaking onto the sensor.
