Knock Sensor Operation

In conjunction with the ignition system, a Knock Sensor (KS) retard system is used. System consists of a KS and PCM. When detonation (engine knock) occurs, knock sensor produces an AC signal. This signal inputs to the PROM or KS module located internal of PCM.

When detonation (engine knock) occurs, the KS produces an AC signal which is to the PCM. The frequency of this signal depends upon knock signals received by the knock sensor. The PCM will retard ignition control timing until signals from the KS cease.

Failure in the KS circuit should set a related Diagnostic Trouble Code (DTC). If a related DTC is not present and the KS system is suspected as the cause of a driveability problem, perform a functional check of the KS. See appropriate SYSTEM & COMPONENT TESTING article.