How to Start a Car With a Bad Crankshaft Sensor?

A crankshaft sensor is an important component in a car’s engine that helps to start the vehicle. It is responsible for sending a signal to the engine control module (ECM) to indicate the position and speed of the crankshaft.

start car with bad crankshaft sensor

This information is used to control ignition timing and fuel injection, as well as to monitor the engine’s performance.

If the crankshaft sensor fails, it can cause a range of issues that can make starting the car difficult or impossible.

In this article, we will discuss how to start a car with a bad crankshaft sensor.

How do I Start My Car with Bad Crankshaft Sensor?

It is not recommended to start your car with a bad crankshaft position sensor. It’s because you will end up damaging crucial components of your car engine costing you lots of money down the line. However, if you are in an emergency situation and need to start your car despite having a bad crankshaft sensor, here is how to do it-

  • Locate the crankshaft position sensor
  • Unplug it
  • Check the wiring for any corrosion or faulty connections
  • If there is no visible damage, then you can attempt to start the car putting back the sensor.
  • However, if it doesn’t work, remove the sensor from the plug and spray starting fluid in the opening from where you removed the sensor.
  • Now, turn the ignition on and try to drive your car. If it’s only crankshaft sensor issue, it should be working as of now.
  • If it starts and then turns off afterward, it might be a problem with your spark plugs.

Symptoms of a Faulty Crankshaft Sensor

There are several signs that a crankshaft sensor may be failing. If you notice any of the following symptoms, it may be time to diagnose and potentially replace the crankshaft sensor:

Check engine light is on:

One of the first indicators of a problem with the crankshaft sensor is the check engine light coming on. This light is triggered by the ECM when it detects a fault in the engine or its components.

Engine won’t start or is difficult to start:

If the crankshaft sensor is not functioning properly, it can cause the engine to either not start at all or to start with difficulty.

This is because the sensor is responsible for sending the necessary information to the ECM to initiate the ignition process.

Engine stalls frequently:

Another symptom of a faulty crankshaft sensor is the engine stalling frequently while driving. This can be caused by the sensor not sending accurate information to the ECM, resulting in the engine misfiring or stalling.

Poor fuel efficiency:

A malfunctioning crankshaft sensor can also lead to poor fuel efficiency. This is because the sensor is responsible for monitoring the engine’s performance and adjusting fuel delivery accordingly. If the sensor is not working properly, the engine may use more fuel than necessary.

Decreased power and acceleration:

Lastly, a faulty crankshaft sensor can cause a decrease in power and acceleration. This is because the sensor is responsible for controlling ignition timing, which affects the engine’s overall performance.

Causes of a Faulty Crankshaft Sensor

There are several reasons why a crankshaft sensor may fail. Some common causes include:

Wear and tear due to age: Like any other component in a car, the crankshaft sensor can wear out over time due to normal wear and tear. This is especially common in older vehicles with high mileage.

Damage from debris or accidents:

The crankshaft sensor can also be damaged by debris or accidents. For example, if the sensor is hit by a rock or other debris while driving, it can become damaged or fail entirely.

Moisture or corrosion:

Finally, moisture or corrosion can cause the crankshaft sensor to fail. If the sensor becomes exposed to moisture, it can rust or corrode, which can interfere with its ability to function properly.

Steps to Start a Car with a Faulty Crankshaft Sensor

If you have determined that the crankshaft sensor is the issue and you need to start the car, there are several steps you can take to do so. These steps include:


Gather all necessary tools and materials. This may include a replacement crankshaft sensor, a multimeter, and any other tools or materials recommended by the manufacturer or a repair manual.

Locate the crankshaft sensor:

The crankshaft sensor is typically located on the engine block near the crankshaft or flywheel. It may be necessary to consult a repair manual or mechanic to find the exact location of the sensor on your specific make and model.

Test the crankshaft sensor:

Once you have located the crankshaft sensor, you can test it using a multimeter. Consult a repair manual or mechanic for specific instructions on how to test the sensor.

Replace the crankshaft sensor (if necessary):

If the crankshaft sensor is faulty, it will need to be replaced. Follow the manufacturer’s instructions or a repair manual to properly replace the sensor.

Clear any fault codes:

After replacing the crankshaft sensor, it may be necessary to clear any fault codes stored by the ECM. Consult a repair manual or mechanic for specific instructions on how to do this.

Test drive the car:

Once the crankshaft sensor has been replaced and any fault codes have been cleared, it is important to test drive the car to ensure that it is functioning properly.

Pay attention to any issues with starting the car, stalling, fuel efficiency, power and acceleration, or any other symptoms that may have been present before the sensor was replaced.

Tips and Precautions

When working on a car, it is important to follow all safety guidelines and take the necessary precautions. Some tips to keep in mind when working on a car with a faulty crankshaft sensor include:

Follow all safety guidelines:

Always follow all safety guidelines when working on a car. This includes wearing protective gear, such as gloves and safety glasses, and following proper lifting techniques.

Consult a mechanic or repair manual:

If you are not familiar with car repair or do not feel comfortable working on your car, it is important to consult a mechanic or repair manual for specific instructions. This will ensure that the repair is done correctly and safely.

Keep a replacement crankshaft sensor on hand:

It is always a good idea to keep a replacement crankshaft sensor on hand in case of future issues. This will save you time and money in the long run, as you will not have to wait for a replacement to be shipped or pay for an emergency repair.


A faulty crankshaft sensor can be a frustrating problem, but it can be fixed with the right tools and knowledge.

By properly diagnosing and replacing the crankshaft sensor, you can get your car back on the road and running smoothly.

Always follow safety guidelines and consult a mechanic or repair manual if you are unsure of how to proceed.

By following these steps, you can confidently start your car with a faulty crankshaft sensor and get back on the road in no time.

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