Estimates last updated October 16, 2025

2020 BMW 840i Crankshaft Position Sensor Replacement Cost

The average cost for a 2020 BMW 840i Crankshaft Position Sensor Replacement is between $223 and $307.

Labor costs are estimated between $98 and $143 while parts are priced between $125 and $164.
This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.

Crankshaft Position Sensor Replacement

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.

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 sensor

Can 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.

BMW Crankshaft Position Sensor Replacement Cost Estimates

The average cost for a Crankshaft Position Sensor Replacement is between $223 and $307 but can vary from car to car.

BMW 840i Crankshaft Position Sensor Replacement Cost by Year

The average cost for a BMW 840i Crankshaft Position Sensor Replacement is between $223 and $307 but can vary from car to car.

Crankshaft Position Sensor Replacement

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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?

What are the symptoms related to a bad crankshaft position sensor?

Can I drive with a crankshaft position sensor problem?

How often do crankshaft position sensors need to be replaced?

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.

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.

RepairPal recommendations for crankshaft position sensor issues

Make sure to use high-quality, OEM sensors. Lesser products will likely cause a repeated repair. When checking this sensor, the vehicle's timing belt should be inspected as well. If the timing belt or timing chain has failed, it should be replaced and the engine should be further inspected.

Can I replace the crankshaft position sensor myself?

Replacing this sensor is easy enough — but what's often tricky is getting the correct diagnosis. Unless you have the proper scanning tools and knowledge, it's likely best to let a professional technician handle this diagnosis and repair.