Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten two ground screws on the body. Refer to GROUND INSPECTION .

Fig 1: Checking Ground Connections

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

OK or NG 

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

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

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check harness continuity between HO2S2 terminal 4 and ECM terminal 78. Refer to WIRING DIAGRAM .
   • Continuity should exist. 
4. Also check harness for short to ground and short to power.

OK or NG 

• OK: GO TO  3.
• NG: Repair open circuit or short to ground or short to power in harness or connectors.

1. Check harness continuity between ECM terminal and HO2S2 terminal as follows. Refer to WIRING DIAGRAM .
   ECM TERMINALS DTC SPECIFICATIONS
   
   

   DTC	Terminals		Bank
   -	ECM	Sensor	-
   P0138	74	1	1
   P0158	55	1	2

   • Continuity should exist. 
2. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM .
   ECM TERMINALS DTC SPECIFICATIONS
   
   

   DTC	Terminals		Bank
   -	ECM	Sensor	-
   P0138	74	1	1
   P0158	55	1	2

   • Continuity should not exist. 
3. Also check harness for short to power.

OK or NG 

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

Check connectors for water.

• Water should not exist. 

OK or NG 

• OK: GO TO  5.
• NG: Repair or replace harness or connectors.

Refer to COMPONENT INSPECTION .

OK or NG 

• OK: GO TO  6.
• NG: Replace malfunctioning heated oxygen sensor 2.

Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

• INSPECTION END