How to Determine a Bad Knock Sensor

The knock sensor is connected to your car's engine block and sends signals to your car's ECM (Electronic Control Module) when the engine is knocking. The sensor makes sure your car is getting enough fuel from your engine. It also helps fuel burn smoothly and prevents fuel from exploding in the cylinder. A defective knock sensor can cause damage to your head gasket as well as performance issues. There are ways you can find out if the knock sensor is defective.

Instructions

1. Drive your automobile around and listen for knocking sound coming from your engine. These sounds indicate a probable knock sensor malfunction. A continuous knocking sound indicates that the knock sensor is damaged. The knocking sound is most commonly heard when you are driving at high speeds.

2. Check your automobile for acceleration problems. A defective knock sensor will cause your car to run sluggishly and not allow it to reach high speeds as quickly. A defective knock sensor will cause your car engine to exert more effort to reach the desired speed.

3. Take note of the odometer reading and monitor your gas mileage. A defective knock sensor will cause your gas to burn faster. If you notice that you are using more gas to drive to work, then the knock sensor could be defective.

4. Take your car to a qualified mechanic for diagnostic testing to confirm your suspicions.

References

• Car Stuff: Knock Sensor Description
• Well's Counterpoint: Knock Sensors Do Two Jobs PDF
• 4DSC.com: Knock Sensor FAQ and Replacement