Symptoms Of A Bad Knock Sensor

When the air-fuel mixture self-ignites too quickly, “knocking” occurs. The cylinder head gasket and cylinder head are most hurt by persistent knocking. The knock sensor sends a signal to the ECU after detecting the high-frequency engine vibrations that are characteristic of knocking. But how do you tell if the knock sensor itself has gone bad since it won’t be able to detect a knocking engine?

Symptoms Of A Bad Knock Sensor

Check Engine Light

The engine light will come on, and an associated diagnostic problem code (DTC) will be set off when the Powertrain Control Module (PCM) discovers a bad knock sensor or voltage circuit.

Engine Making Noises

The PCM might not be able to detect or adjust the spark knock frequency if the knock sensor fails. The engine may make a metallic pinging noise if the sensor fails. Additionally, you’ll observe that the noise is most noticeable while the engine is working under a heavy load.

Bad Engine Performance

Engine performance may suffer as a result of the PCM incorrectly changing the ignition timing brought on by a damaged engine knock sensor. When traveling at high speed or when the car is pulling a heavy load, the engine might not feel right. Even if the check engine light is not on, you should have it checked by a certified mechanic.

Power Loss

Your car will probably lose power after the engine control unit notices the knock sensor isn’t operating properly. The engine’s maximum octane rating and how heavily it relies on knock sensor input will determine how much power is lost.

High-compression and flex-fuel engines are the ones that lose the most power in automobiles. That’s because the power loss delays the engine timing and keeps the transmission out of drive until the knock sensor is fixed.

Conclusion

If any of these signs are noticed, a scan tool or code reader should be used to check for trouble codes related to the knock sensor. Additionally, a timing light, mechanic’s stethoscope, multimeter, compression tester, and borescope can be used for further diagnosis. If it is confirmed that the knock sensor is faulty, it should be replaced promptly to prevent further damage to the engine.