Japanese Subaru Knock Sensor

Description

Signs of a Bad Knock Sensor

When the knock sensor fails, it will usually cause one or more noticeable symptoms. The most common knock sensor problems include:

Illuminated Check Engine Light

The most common sign of a bad knock sensor is an illuminated check engine light. When the PCM detects a problem with the knock sensor or its circuit, the module will turn on the check engine light and store a corresponding diagnostic trouble code (DTC) in its memory.

Pinging Noise From the Engine

If the knock sensor fails, the PCM may not recognize or correct spark knock. As a result, you may hear a metallic pinging noise from the engine. The noise is often most noticeable when the engine is under a heavy load.

Poor Engine Performance

A faulty knock sensor can also cause the PCM to misadjust the ignition timing, resulting in poor engine performance. If you’re wondering, “Will a knock sensor cause a no-start?” it’s rare for this to happen, although a bad knock sensor can make starting your vehicle more difficult.