Bad Crankshaft Sensor: Symptoms And How To Replace It

You will find a crankshaft position sensor in all modern-day vehicles. It is basically a component to monitor the rotational speed and position of the crankshaft. A report is sent to the engine control unit in the same way to make appropriate adjustments in case of malfunctioning.

There are many symptoms of a crankshaft position sensor failure that a car owner would know and must watch out for. Many models of engine stop to function altogether if the component fails to send signals properly.

Common Crankshaft Sensor Failure Symptoms

Speed and position are the two key parameters of the crankshaft that a car’s computer utilizes for calculations and engine management. This will help you understand the importance of a sensor to work properly without a glitch.

Let’s have a look at some of the crankshaft position sensor failure symptoms so you can take action timely, in case you notice such symptoms in your vehicle (I hope you don’t).

1.      Engine Light On

The engine light can turn on due to a number of reasons, one of which is the sensor problem. It is also a symptom of the crankshaft position sensor issue. It might stop working due to sometimes overheating which will make the engine light to turn on.

If this happens to you, try cooling down the engine for a while so the sensor is also cooled down and the light may go off. If this doesn’t help, visit a mechanic to get an overall checkup of your car’s computer to determine the source of the issue.

2.      Engine Vibrations

The main cause is usually engine vibrations. Failure of the sensor means the crankshaft position isn’t being monitored, causing heavy vibrations in the engine. As a result, the juddering will affect engine power and mess up with the mileage recording.

3.      Slow Response of Accelerator

Sometimes, the accelerators might not deliver abrupt responses. If there is an issue with the sensor, the correct information won’t be sent regarding the cylinders’ position. The gap in receiving data and adapting changes makes the engine suffer. This is the reason why the accelerator fails to provide any real-time response.

4.      Erratic Starting

This is among the most serious symptoms of the crankshaft position sensor. A malfunction code is received by the computer when the sensor is gone completely. It starts with difficulty in the beginning and leaving the car dead if it doesn’t get fixed. The problem of starting can be a result of electrical connections or issues with the circuit.

5.      Cylinder Misfiring

This is a common response to issues with the sensor. A failing sensor also fails to provide accurate information about the position of the piston, causing cylinder misfiring. Any issue with the spark plug also draws a similar response. Nevertheless, if the issue remains after handling all other issues, the culprit has to be the sensor only.

6.      Stalling and Backfiring

Another issue that may indicate a problem with the sensor is this, wherein the engine may go off suddenly. The car will be running, but after some time, the engine will turn off on its own, with misfiring occurring in the same way. If these signs are constantly ignored, the engine will permanently shut off.

Testing a Crankshaft Position Sensor

If any of these symptoms occur in your vehicle, it is time to check the sensor to see if it is the cause of the problem. There are a few steps you can take to test the sensor before calling experts to test the voltage output.

After having tested the voltage output, you can compare the measured values with the specifications in the manual. It is an easy way to find that the crankshaft sensor is not working properly. The connection of the voltmeter and the wires on the sensor connector can detect if the voltmeter is equipped with the right probes, which is a needle multimeter.

If you have a digital multimeter adjusted to millivolt range, start the engine and check the value according to the manufacturer’s specifications. If the vehicle manual indicates the specified resistance value, you can check the sensor without cranking the engine.

How to Replace a Crankshaft Sensor

If you are confident about your car fixing skills, then we would recommend you to try replacing the crankshaft sensor yourself. However, if you are unsure that you do not have the tools or enough space for repair, it is best to let an expert who knows the basic steps to take care of it.

  • It may be useful to disconnect the battery, starting from the negative pole to prepare the work area.
  • You will have to lift the vehicle to enter under it and reach the sensor. Make sure that your vehicle is in a safe position.
  • Start by releasing the plastic clip to disconnect the electrical connector. Then pull the connector carefully. You might have to rotate it from one side to another to loosen it.
  • Check for the connector if it is not corroded. In case the engine stops, then you know the cause.
  • Clean and replace the pigtail. If necessary, remove the sensor fixing screws. Usually, there are one or two 10mm screws holding the sensor in place.
  • Remove the sensor if it is firmly attached. Remember to twist it gently and then pull it out. If it doesn’t work, release it. It can work as a useful tool to remove the door panel clip. Don’t put too much pressure on it, because you may break the sensor when the old sensor is outside.
  • You must prepare a fresh start by lightly lubricating it to make it easier to position, clean the position sensor window before placing a new sensor and push it firmly into the place to replace the retaining screws.
  • Reconnect the connector electrical, make sure the connector terminal is fully inserted.
  • Replace any other parts removed to access the sensor, then carefully tilt the vehicle.
  • Reconnect the battery starting from the positive pole.

You are now ready to test the new sensor and return to driving without problems.

In Conclusion

Take care of your vehicle, and pay attention to small changes in how it works. It is the best way to ensure excellent vehicle performance and fuel efficiency. The crankshaft sensor is just one of many sensors that have been ignored to improve your vehicle’s performance. Ignoring the symptoms of a bad crankshaft sensor can lead to many problems that could otherwise impede resources.