Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION  ".
   Fig 1: Loosening Ground Screws

   Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

1. OK: GO TO 2.
2. NG: Repair or replace ground connections.

1. Loosen and retighten corresponding heated oxygen sensor 1.
   Fig 2: Loosening And Retightening Heated Oxygen Sensor 1

   Courtesy of NISSAN MOTOR CO., U.S.A.

   Tightening torque: 50 N.m (5.1 kg-m, 37 ft-lb) 

   1. : GO TO 3.

1. Disconnect heated oxygen sensor 1 harness connector.
   Fig 3: Disconnecting Heated Oxygen Sensor 1 Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
2. Disconnect ECM harness connector.
3. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78. Refer to WIRING DIAGRAM  .
   1. Continuity should exist. 
4. Also check harness for short to ground and short to power.

OK or NG

1. OK: GO TO 4.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.

1. Check harness continuity between ECM terminal and HO2S1 terminal as follows. Refer to WIRING DIAGRAM  .
   Fig 4: DTC And Terminals Reference

   Courtesy of NISSAN MOTOR CO., U.S.A.
   1. Continuity should exist. 
2. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM  .
   Fig 5: DTC And Terminals Reference

   Courtesy of NISSAN MOTOR CO., U.S.A.
   1. Continuity should not exist. 
3. Also check harness for short to power.

   OK or NG

   1. OK: GO TO 5.
   2. NG: Repair open circuit or short to ground or short to power in harness or connectors.

Check connectors for water.

1. Water should not exist. 

OK or NG

1. OK: GO TO 6.
2. NG: Repair or replace harness or connectors.

Refer to "COMPONENT INSPECTION  ".

OK or NG

1. OK: GO TO 7.
2. NG: Replace malfunctioning heated oxygen sensor 1.

Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  ".

1. : INSPECTION END