Bad Crankshaft Position Sensor Symptoms

A crankshaft position sensor is an electronic device designed to monitor the position and rotational speed of the crankshaft. It is found on all vehicles with an internal combustion engine. Many engines can not run without a crankshaft position sensor. Also, the crankshaft position sensor is the most important sensor among all engine management sensors.

As the crankshaft sends information to the engine control unit, if your crankshaft position sensor is faulty, it won’t send an accurate signal. But there are some bad crankshaft position sensor symptoms that alert the user about a problem that needs to be serviced.

Reasons For Crankshaft Position Sensor Failure:

There are a few reasons for the crankshaft position sensor failure:

  • Faulty circuits can cause the failure of the crankshaft position sensor.
  • Excessive build-up of heat can melt plastic wearing of crankshaft position sensor which may also result in crankshaft position sensor failure
  • If the engine control module and crankshaft position sensor lose connection because of any damaged wiring.

Faulty Crankshaft Position Sensor Symptoms:

Here are some most common symptoms of faulty crankshaft position sensor:

1. Vehicle Stalls:

If there’s any problem with the wiring or crankshaft position sensor itself, the crankshaft signal will be cut off causing the engine to stall. If there’s any problem with the wiring or connection between the crankshaft position sensor and engine control module, they both will lose their connection. This can cause a vehicle to stop as the engine control module won’t get any signal.

2. Having Hard Time Starting Car:

Another sign of a faulty crankshaft position sensor is that you having a hard time starting your car. Your crankshaft position sensor starts monitoring the position and rotational speed the moment you start your vehicle. So if there is a fault within the crankshaft position sensor, it will halt the process and the engine won’t turn on.

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3. Check Engine Light Comes On:

If you see the check engine light blinking that means there is something wrong with the crankshaft position sensor and it will activate the check engine light. This is to alert the user about a fault in the crankshaft position sensor. Check engine light may come on for many reasons including crankshaft position sensor failure, and when you see this light, it means now is the time to show your vehicle to a mechanic.

4. Engine Vibrations:

One of the symptoms of a bad crankshaft position sensor is drastic vibrations coming through your vehicle’s engine. You may even feel these vibrations from your steering wheel. If you notice a heavy increase in vibrations, this may be because of a bad crankshaft position sensor.

5. Cylinder Misfires:

There may be a misfire inside one or more chamber cylinders as a failed or faulty crankshaft position sensor won’t be able to send proper information about piston position to the engine control unit. Sometimes this happens because of bad spark plugs too but if it’s not bad spark plugs then it may be because of a bad crankshaft position sensor.

6. Decreased Engine Performance:

Because of a bad crankshaft position sensor, the engine control unit won’t be able to know the correct position which will cause a delay in the control unit’s operations and performance of the engine. Sometimes you may face a situation in which the engine won’t even respond. As this can be very dangerous, it’s recommended to take your vehicle to the repair shop.

A crankshaft position sensor is also responsible for managing fuel injectors. If the crankshaft position sensor is bad it won’t be able to trigger the fuel injectors and because of this, your vehicle won’t start.

How To Fix A Bad Crankshaft Sensor?

  1. To avoid any circuit in a car’s electrical system, disconnect the battery.
  2. Check for the battery’s location and remove the negative terminals.
  3. To access the sensor first you will have to remove the starter motor.
  4. Locate the crankshaft position sensor and release the electrical connector.
  5. To release the electrical connector, you will need to push down or pull out a plastic chip holding the sensor.
  6. Now when the electrical connector is removed, check if there’s any rust and clean it.
  7. After this remove the sensor bolt using a wrench and then remove the sensor.
  8. Now match and reinstall a new crankshaft sensor.
  9. Reconnect the battery.
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Replacing the crankshaft sensor is a very critical and complex process so it’s better to let a professional take care of it. And the question is that can I fix a bad crankshaft position sensor or should I do it?

Can I Fix A Bad Crankshaft Position Sensor?

Well, this whole process of checking and fixing a bad crankshaft sensor is very complex. You can make a guess that there is something wrong with the crankshaft position sensor based on the above symptoms. If you notice more than one of the bad crankshaft position sensor symptoms, then you need to take your vehicle to a repair shop or contact a professional mechanic.

A mechanic will be able to diagnose the problem and will be able to fix it well. If you are thinking about fixing it by yourself, don’t because even a little mistake may cause you a bigger problem. Don’t try to fix this unless you have the proper knowledge and can carry it out perfectly.

Replacement Cost:

It may cost you around $120-$300 to get a crankshaft position sensor replaced. If you buy a crankshaft sensor alone, it will cost you around $70-$120 and labor cost may be around $50-$180.


At last, it is recommended to take your vehicle to a professional mechanic if possible or contact one as soon as you notice more than one of the above bad crankshaft position sensor symptoms. If suddenly your vehicle stops or stalls on a road with traffic it can be very dangerous and can even cause an accident.

You can also read the error code if you have an OBD2 scanner, as it will help you diagnose the problem. The error code for crankshaft position sensor “A” malfunctioning is P0335 and P0304 for cylinder 4 misfire detected.

Thank you.

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