A bad crankshaft sensor causes symptoms like the check engine light, difficulty starting/stalling, rough idling/misfiring, uneven acceleration, and poor fuel economy, because the engine control unit (ECU) loses crucial data for ignition and fuel timing, leading to erratic engine performance or failure to start. You can confirm it by using an OBD-II scanner for codes like P0335, or by testing the sensor with a multimeter.
A bad crankshaft position sensor (CKP) causes major engine issues like difficulty starting, stalling, rough idling, misfires, poor acceleration, and reduced fuel economy, often triggering the Check Engine Light because the computer loses crucial timing data for fuel and spark. You might also notice engine vibrations or hesitation, and in severe cases, the engine won't start at all.
Test the Two-Wire Sensor for Continuity
A crankshaft position sensor test involves getting a multimeter and setting it to the 20,000 ohms setting. Connect the two multimeter leads to the two metal prongs on the sensor. If the sensor can detect a value of 200 to 1000 ohms, then your sensor is running properly.
If your engine refuses to start and your ignition continues to click over without any success, you may be able to blame it on a faulty crankshaft position sensor. Without it, your engine will have trouble knowing when to fire the spark plugs or even inject fuel, so good luck getting things started!
However, when a sensor fails or sends incorrect data, you may experience poor acceleration, increased fuel consumption, rough idling, or even a no-start condition. Diagnosing the problem early can save you thousands in repairs and prevent breakdowns.
The crank sensor is the basic input the ECM/PCM uses for ignition timing and fuel injection. If there's no crank sensor input, there'll be no ignition and no fuel injection. This means the vehicle won't even start.
Sensor Connection Issues: Faulty wiring, loose connections, or improper installation can cause intermittent or complete loss of signal from a sensor, resulting in unreliable measurements or complete sensor failure.
1. Do I need to reset the ECU after replacement? Yes, clearing the ECU helps the system relearn the new sensor. You can do this with an OBD-II scanner or by disconnecting the battery briefly.
With a Check Engine Light on, trouble codes will be stored in the onboard computer that can help identify whether the crank sensor is faulty. DTCs will often be directly related to the crank sensor, and they're often accompanied by other codes related to misfires, timing, or injection.
Most manufacturers say a sensor lasts between two and five years. In practice, however, both the environment sensors operate in and how they're maintained can shorten their life significantly. The good news is that most performance issues are preventable with a little knowledge and the right strategy.
This guide covers the complete crankshaft position sensor replacement process, from identifying symptoms to testing. With basic tools and 30 to 60 minutes, most DIYers can complete this engine sensor repair.
Because the fuel injection process will be hampered by receiving incorrect signals from a faulty crankshaft sensor, the fuel may not combust in the engine properly. Not only can this cause the engine to sputter, but also reduce power. This leads to more fuel being consumed to achieve the same performance.
Knocking or Clunking Noises from the Engine
One of the first signs of a bad crankshaft is unusual knocking or clunking noises. This happens when crankshaft journals become worn or bearings begin to fail. These noises are typically deeper and more metallic than valve tapping or injector ticks.
The average cost for a Crankshaft Position Sensor Replacement is between $218 and $329. Labor costs are estimated between $135 and $198 while parts are priced between $83 and $131. This range does not include taxes and fees, and does not factor in your unique location.
Average Lifespan of a Crankshaft Sensor
On average, you can expect it to hold up for around 100,000 miles, sometimes stretching to 150,000 if the car's well-kept. That's about the same lifespan as many ignition parts, which makes sense since they're all tied to engine timing.
How quickly does a car adapt after a new MAF sensor? Most cars adjust within a few drives, but full reset may take 50–100 miles depending on ECU and driving style.
Set the multimeter to DC voltage and probe the sensor's signal wire. A good sensor fluctuates between 0.1V and 0.9V. A steady reading or no voltage means the sensor is bad.
Not necessarily. The oxygen sensor simply reports the data that it gathers. For example, if you are getting a lean mixture code, you may have a vacuum leak or a faulty fuel injector.
Adjust your camera to the lowest ISO and smallest aperture it can handle. Blur your focus as you take a photo of a white surface. Upload the image to your computer and zoom in to find spots. If you see spots on your image, it's time to clean your sensor.