Electronic Spark Control (ESC) System W/O ESC Controller (C-5)
- An open or short circuit on the ESC wire to the ECM will set a related trouble code. A false detonation signal will not cause ECM to set a code.
- If a "Scan" tester is available, connect it to the ALDL connector. Tap on engine next to knock sensor and note "knock" parameter. Knock should be indicated on "Scan" tester.
- If a "Scan" tester 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-ECM circuit.
- On vehicles equipped with automatic transmission, it may be necessary to place transmission in Drive for timing change to occur. Also, see KNOCK SENSOR in ENGINE SENSORS & SWITCHES .