Diagnostic Procedure

CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check resistance between ECM terminal 15 and engine ground. Refer to WIRING DIAGRAM .
  NOTE: It is necessary to use an ohmmeter which can measure more than 10 MΩ.
  
  Resistance: Approximately 530 - 590kΩ [at 20°C (68°F)]
4. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 4.
2. NG: GO TO 2.
CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector and knock sensor harness connector.
3. Check harness continuity between knock sensor terminal 1 and ECM terminal 15.
  Refer to WIRING DIAGRAM .
  
  Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 3.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK KNOCK SENSOR
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK: GO TO 5.
2. NG: Replace knock sensor.
RETIGHTEN GROUND SCREWS
Loosen and retighten engine ground screws.

Fig 2: Identifying Engine Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
1. GO TO 5.
CHECK INTERMITTENT INCIDENT
Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END