Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten heated oxygen sensor 1.

   Tightening torque : 40 - 60 N.m 

   (4.1 - 6.1 kg-m, 30 - 44 ft-lb) 

   1. : GO TO 2.
   Fig 1: Tightening Heated Oxygen Sensor 1

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

1. Disconnect heated oxygen sensor 1 harness connector and ECM harness connector.
   Fig 2: Disconnecting Heated Oxygen Sensor Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
2. Check harness continuity between ECM terminal 50 and HO2S1 terminal 2.

   Refer to WIRING DIAGRAM .

   Continuity should exist. 

3. Check harness continuity between ECM terminal 50 or HO2S1 terminal 2 and ground.

   Refer to WIRING DIAGRAM .

   Continuity should not exist. 

4. Also check harness for 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 heated oxygen sensor 1 harness connector for water.

Water should not exist. 

OK or NG 

1. OK : GO TO 4.
2. NG : Repair or replace harness connector.

Refer to "COMPONENT INSPECTION ".

OK or NG 

1. OK : GO TO 5.
2. NG : Replace heated oxygen sensor 1.

Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

1. : INSPECTION END.