Code 52, Knock Sensor Circuit, Open Or Shorted Circuit: Notes

Knock sensor (located in rear of engine block) is used to detect engine knock (abnormal vibration). PCM will retard ignition timing based on signal received from knock sensor when engine knock is present. Knock sensor is constructed of a piezoelectric element which generates an AC voltage when it becomes deformed (vibration or engine knock detected). Knock sensor sends this voltage signal to PCM which in turn retards ignition timing. Engine knock will no longer be detected with reduced ignition timing.

Code 52 will set if an open or short in knock sensor circuit is present with engine speed 1200-6000 RPM for at least .5 second.

1. Checks for possible shorts in knock sensor circuit.
2. Determines if knock sensor is faulty, Black wire is open or shorted, or PCM is faulty.