Code 23 Or 53: Knock Sensor
NOTE:
Repair any engine knocking sounds before performing test.
- Turn ignition off. Remove BACK-UP fuse (10-amp) from underhood fuse/relay box for 10 seconds to reset ECM. Warm engine until cooling fan comes on. With transmission in Neutral, hold engine speed at 3000-4000 RPM for 10 seconds. Check for fault codes. If Code 23 or 53 is not present, problem is intermittent. Check for poor connections at ECM, knock sensor and wiring harness connectors. Test drive vehicle and retest.
- If Code 23 (knock sensor No. 1) or Code 53 (knock sensor No. 2) exists, turn ignition off. Connect ECM Test Harness (07LAJ-PT3010A ) to ECM wiring harness connectors, leaving ECM disconnected. See Figure . Disconnect knock sensor connector No. 308, located on left shock tower.
- Check for continuity between test terminal C1 (sensor No. 2) or C3 (sensor No. 1) and body ground. If continuity is not present, go to next step. If continuity is present, repair short in Red/Blue wire (knock sensor No. 1) or Orange/White wire (knock sensor No. 2) between ECM connector and knock sensor. See Fig 1 .
- Disconnect knock sensor connector No. 308. See Fig 1 . Check continuity between test terminal C3 and Red/Blue wire terminal at knock sensor connector No. 308 (knock sensor No. 1) or between test terminal C1 and Orange/White wire terminal at knock sensor connector No. 308. If continuity is not present, repair open in wire between ECM connector and knock sensor.
- If continuity is present, replace ECM with a known good unit. Warm engine until cooling fan comes on. With transmission in Neutral, hold engine speed at 3000-4000 RPM for 10 seconds. Check ECM for fault codes. If Code 23 or 53 is present, replace appropriate knock sensor. If Code 23 or 53 is not present, replace original ECM.