Knock Sensor (KS) System Without KS Module
- An open or short circuit on KS wire to PCM will set a related diagnostic trouble code. A false detonation signal will not cause PCM to set a code.
- If a scan tool is available, connect it to the DLC. Tap on engine next to knock sensor and note KNOCK parameter. Knock should be indicated on scan tool.
- If a scan tool is not available, connect tachometer to engine. Start engine and hold RPM above idle. Using a metal object, tap on engine close to knock sensor. A noticeable decrease in engine RPM should occur. If no NOTICEABLE RPM decrease occurred, check knock sensor-to-PCM circuit.
- On vehicles with automatic transmission, it may be necessary to place transmission in Drive for timing change to occur. Also, see KNOCK SENSOR (KS) under ENGINE SENSORS & SWITCHES .