Code 52, Knock Sensor Signal, Open Or Short Circuit
The knock sensor is used to detect engine detonation. ECM will retard the electronic spark timing based on signal received from knock sensor. Knock sensor sends an AC voltage signal to the ECM through the Black wire and should measure about 100-300 mV AC. The amplitude and signal frequency are dependent upon the knock level.
If Black wire to knock sensor becomes open or shorted to ground, voltage will drop to less than 100 mV AC. If this condition is met for about 5 seconds, Code 52 will be stored.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This test determines if knock sensor will produce a signal.
- This test determines if knock sensor will detect a knock signal.
- This test determines if ECM is pulling the knock sensor line low.