What is Crankshaft Position Sensor? | Signs of a Bad Crankshaft Position Sensor

What is Crankshaft Position Sensor?

The crankshaft position sensor measures every revolution of the crankshaft when the engine is running.

Modern vehicles are jam-packed full of sensors that keep everything operating the way it should. But while all these electronics create far more efficient and powerful vehicles, they can also create massive headaches when something goes wrong.

Bad Crankshaft Position Sensor Symptoms

1) Check Engine Light

Like we said before, the most common symptom of a bad crankshaft position sensor is a check engine light. The good news is that if you have a check engine light, then your ECM has reverted to default measurements.

While this might cause a few performance issues, it should help prevent further damage from occurring. However, the longer you leave the problem unaddressed, the worse it will become.

2) Excessive Engine Vibrations

If your engine has a faulty crankshaft position sensor, then it isn’t optimizing any performance. Even worse, it might be utilizing incorrect readings to determine fuel and ignition timing. If the ECM doesn’t time things correctly, you’re in for a bumpy ride.

Even worse, the problem is only going to get worse until you fix it, and it’s only a matter of time until further damages occur.

3) 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 sign of a wiring problem. However, a bad crankshaft position sensor can also produce this symptom.

4) Uneven Acceleration

With inaccurate input coming from the crankshaft position sensor, the engine control unit can’t make the adjustments to spark timing and fuel injection as the engine speed increases. Slow or uneven acceleration can result from a lack of accuracy and make it difficult to maintain a constant speed.

5) Reduced Engine Performance

Whether you have a check engine light or not, a faulty crankshaft position sensor will lead to reduced engine performance. Whether it’s default values or the wrong values entirely, anything less than optimal timing is going to reduce your overall performance.

Top speed and acceleration are the two most significant areas that you are going to see reduced performance.

Keep in mind that an engine that isn’t performing correctly is also going to have a reduction in fuel economy, but unless you’re paying close attention to how many miles you get out of each tank, you might not notice.

6) Difficulty Starting Your Vehicle

If your defective crankshaft position sensor is extremely out of sync, you might have trouble getting your vehicle started. Furthermore, you might have difficulty keeping it started.

This is usually only a problem when the problem has persisted for some time, and you likely have various other underlying issues too. Moreover, it’s not usually a problem if you have a check engine light and the ECM has defaulted to predetermined values.

Instead, it’s a problem when the crankshaft position sensor is feeding inaccurate readings and your ECM doesn’t realize it.

7) Engine Misfires

While it’s unlikely that a vehicle with a check engine light on will misfire, if the ECM uses incorrect positions of the crankshaft, it’s incredibly likely. Even worse, if you have an engine that’s misfiring, it’s only a matter of time until engine damage occurs.

The longer you let a misfire happen, the worse it’ll get, and the more expensive the eventual repairs will be. If you have a misfire, get repairs as soon as possible.

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