Will a Crankshaft Sensor Keep a Car from Starting?
Can a Bad Crankshaft Position Sensor Prevent a Car from Starting?
Yes, a faulty crankshaft position sensor can prevent a car from starting. The crankshaft position sensor (CKP sensor) is responsible for monitoring the position and speed of the crankshaft and sending that information to the engine control module (ECM). If the ECM doesn’t receive a signal from the sensor, it won’t know when to fire the spark plugs or inject fuel, causing a no-start condition.
How a Bad Crankshaft Sensor Causes a No-Start Issue
Signs That a Bad Crankshaft Sensor Is Preventing Your Car from Starting
✅ Cranks but Won’t Start – The engine turns over but doesn’t fire.
✅ No Spark from Ignition Coils – A missing crankshaft signal means the ignition system won’t fire.
✅ Check Engine Light On – Codes like P0335 (Crankshaft Position Sensor Circuit Malfunction) may appear.
✅ No Fuel Injection – The ECM may not activate fuel injectors without the sensor data.
✅ Engine Stalls While Driving – If the sensor is failing, the engine may shut off unexpectedly.
How to Fix a No-Start Issue Caused by a Bad Crankshaft Sensor
- Check for Trouble Codes – Use an OBD-II scanner to look for P0335, P0336, or related codes.
- Test the Crankshaft Sensor – Use a multimeter to check for proper resistance and voltage.
- Inspect Wiring and Connectors – Look for damaged wires, loose connections, or corroded terminals.
- Replace the Crankshaft Position Sensor – If faulty, install a new sensor.
- Perform a Crankshaft Relearn Procedure – After replacement, some cars require a relearn with an OBD-II scanner.
- Check the Battery and Starter – Ensure the starter and battery are functioning properly.
Final Thoughts
Yes, a bad crankshaft sensor can prevent the car from starting because the ECM won’t receive the necessary signal to fire the engine. If your car cranks but won’t start, checking and replacing the crankshaft position sensor may solve the issue.
FAQs
1. Will disconnecting the battery reset a bad crankshaft sensor?
No, resetting the battery won’t fix a faulty sensor—it must be tested and replaced if bad.
2. Can I drive with a bad crankshaft sensor?
If the car starts, it may stall unpredictably, making it unsafe to drive.
3. How much does it cost to replace a crankshaft position sensor?
- Parts: $40–$200
- Labor: $100–$300
- Total Cost: $150–$500
4. How do I know if my crankshaft sensor is bad or if it’s something else?
Use an OBD-II scanner to check for crankshaft sensor-related trouble codes. If present, testing the sensor’s voltage and wiring will confirm if it’s faulty.
5. Will a car start with a bad crankshaft sensor but a good camshaft sensor?
Sometimes. Some cars can use camshaft sensor data as a backup, but others require both sensors to start.
Also Check:
• Can a Crankshaft Sensor Cause a No-Start Condition?
• Will a Crankshaft Sensor Cause a Misfire?
• Can a Bad Camshaft Sensor Cause a Misfire?
