Diagnostic Procedure

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Loosen and retighten engine ground screws.
  
  Fig 1: Identifying Engine Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Disconnect ECM harness connector and A/F sensor 1 harness connector.
4. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
  
  Fig 2: Disconnecting A/F Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 3: ECM & A/F Sensor 1 Terminal Chart
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Continuity should exist.
5. Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to WIRING DIAGRAM .
  Continuity should not exist.
6. Also check harness for short to power.
OK or NG
1. OK: GO TO 2.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK INTERMITTENT INCIDENT
Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

OK or NG
1. OK: Replace A/F sensor 1.
2. NG: Repair or replace.