Skip to content
![7 Bad Crankshaft Position Sensor Symptoms [+ How to Fix]](http://www.ancel.com/cdn/shop/articles/Car_Facebook_Post.png?v=1721986844&width=1)
The crankshaft position sensor is a key part of your car's engine system.
It monitors the position and speed of the crankshaft, sending this information to the engine control unit (ECU) to help the engine run smoothly.
When this sensor goes bad, it can cause a lot of problems with how your car runs. In this guide, we'll go over the signs of a bad crankshaft position sensor and how you can fix it.
Your Crankshaft Sensor is Bad
1. Check Engine Light Comes On
One of the first things you'll notice if the crankshaft position sensor is going bad is the check engine light coming on.
The ECU depends on the data from this sensor, and if something's off, it'll trigger the check engine light to let you know there's a problem.
2. Engine Misfires
If the crankshaft position sensor isn't working right, you might experience engine misfires.
This means the engine doesn't run as smoothly as it should because the spark plugs aren't firing at the right times.
This happens because the sensor isn't giving the ECU the right information.
Related Reading: Car Codes of Camshaft Actuators and How to Fix Them
3. Hard to Start the Engine
Another sign is difficulty starting the engine.
The crankshaft position sensor helps the ECU know where the crankshaft is so it can start the engine properly.
If the sensor is faulty, the engine might take a long time to start or not start at all.
4. Engine Stalls
A bad crankshaft position sensor can cause your engine to stall unexpectedly.
This can happen when you're idling or driving, making it dangerous.
The engine might suddenly cut out because the ECU loses track of the crankshaft's position, messing up the fuel injection and ignition.
5. Slow Acceleration
If your car has poor acceleration or hesitates when you press the gas pedal, it could be because of a bad crankshaft position sensor.
The ECU needs accurate data to adjust the fuel and timing for smooth acceleration.
If the sensor is giving bad information, your car might not respond well when you hit the gas.
6. Rough Idling
When the crankshaft position sensor isn't working right, it can cause rough idling. This means the engine runs unevenly or shakes when you're not moving.
The ECU has trouble keeping a steady idle speed without the right input from the sensor.
7. Uses More Fuel
A bad crankshaft position sensor can also lead to reduced fuel efficiency.
The engine might use more fuel than it should, costing you more money and being worse for the environment.
How to Fix a Bad Crankshaft Sensor
Find the Problem
Before you replace the crankshaft position sensor, make sure to diagnose the issue correctly.
Use the car scanner ANCEL X7 to check for error codes related to the crankshaft position sensor.
This tool is excellent for its features
- ECU coding for VW and Audi
- Anti-theft key capabilities
- 10+ hot reset services (IMMO key, Oil reset, EPB reset, DPF reset, ABS bleeding SAS reset, BMS registration, TPMS service, TPS reset, Injector reset)
"I recently purchased the ANCEL X7 for my VW and I couldn't be happier.
This scanner made it easy to diagnose the crankshaft position sensor issue by providing clear error codes.
The ECU programming for my car was straightforward, and I appreciated the full system diagnostics which gave me peace of mind.
The hot reset services like the oil reset and ABS bleeding are lifesavers, and the anti-theft key feature is a great bonus.
I highly recommend the ANCEL X7 for anyone needing a reliable car scanner!" – John, Satisfied User
Locate the Sensor
The crankshaft position sensor is usually located near the crankshaft pulley, flywheel, or engine block. Check your car's service manual for the exact location, as it can vary by make and model.
Get Your Tools Ready
To replace the crankshaft position sensor, you'll need the following tools and materials:
- New crankshaft position sensor
- Socket set
- Ratchet
- Screwdriver
- Jack and jack stands (if necessary)
- Safety gloves and glasses
Disconnect the Battery
For safety, disconnect the negative battery terminal before starting the replacement process.
This prevents any accidental short circuits or electrical shocks.
Remove the Old Sensor
Find the crankshaft position sensor and disconnect its electrical connector.
Use the right socket and ratchet to remove the bolt(s) holding the sensor in place. Carefully take out the sensor.
Put in the New Sensor
Put the new crankshaft position sensor in place, line it up with the mounting hole, and secure it with the bolt(s).
Reconnect the electrical connector to the sensor. Make sure everything is tight and secure.
Reconnect the Battery
Reconnect the negative battery terminal tightly. This will restore power to your car's electrical system.
Test the Fix
Start the engine and see how it runs. Use the OBD2 scanner to clear any stored error codes and check for new ones.
Make sure the check engine light is off and the engine runs smoothly without any of the symptoms mentioned earlier.
Conclusion
By following the steps in this guide, you can diagnose and replace a faulty sensor, ensuring your engine performs well.
Regular maintenance and quick attention to any issues will help keep your vehicle in top shape.
FAQs
How much does it cost to replace a crankshaft position sensor?
The cost to replace a crankshaft position sensor can vary depending on your vehicle’s make and model, as well as the labor rates in your area. On average, the replacement cost ranges from $120 to $300, including parts and labor.
Can I drive my car with a bad crankshaft position sensor?
While it might be possible to drive with a failing crankshaft position sensor, it is not recommended. Driving with a bad sensor can lead to poor engine performance, stalling, and potentially leave you stranded if the engine fails to start.
What causes a crankshaft position sensor to fail?
Crankshaft position sensors can fail due to age, heat, and exposure to oil and grime. Electrical issues, such as damaged wiring or connectors, can also cause the sensor to fail. Regular maintenance and keeping the engine area clean can help extend the life of the sensor.
