Turn the ignition switch OFF. Disconnect the knock sensor 3P connector. Turn the ignition switch ON (II). Measure voltage between knock sensor 3P connector terminal No. 1 and body ground. KNOCK SENSOR 3P CONNECTOR Wire side of female terminals Is there about 5 V? YES - Go to step 19. NO - Go to step 15. Measure voltage between ECM/PCM connector terminal A9 and body ground. ECM/PCM CONNECTOR A (31P) Wire side of female terminals Is there about 5 V? YES - Repair open in the wire between the ECM/PCM (A9) and knock sensor. NO - Go to step 16.

Turn the ignition switch OFF. Disconnect ECM/PCM connector A (31P). Check for continuity between ECM/PCM connector terminal A9 and body ground. ECM/PCM CONNECTOR A (31P) Wire side of female terminals Is there about 5 V? YES - Repair short in the wire between ECM/PCM (A9) and the knock sensor. NO - Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM. Substitute a known-good knock sensor and recheck. Is the MIL on and does it indicated DTC 23? YES - Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/PCM. NO - Replace the original knock sensor.