Knock Sensor Circuit (Models Using Knock Sensor With Internal Spark Controller Module)
WARNING: This page is about a different car, the 1997 GMC Vandura, 1997 GMC Forward Control, 1997 Chevrolet Forward Control, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- An open or short circuit on knock sensor wire to PCM will set a related trouble code. A false detonation signal will not cause PCM to set a code.
- If a scan tool is available, connect it to Data Link Connector (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 RPM decrease occurred, check knock sensor to PCM circuit.
- On vehicles equipped with automatic transmission, it may be necessary to place transmission in Drive for timing change to occur. See KNOCK SENSOR under ENGINE SENSORS & SWITCHES .