3. Check Heated Oxygen Sensor 1 Circuit For Open And Short

1. Turn ignition switch OFF.
2. Disconnect corresponding heated oxygen sensor 1 (HO2S1) harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal and HO2S1 terminal as follows.

   Refer to Wiring Diagram.

   Fig 1: Checking Heated Oxygen Sensor 1 Circuit For Open & Short

   Courtesy of NISSAN MOTOR CO., U.S.A.
   1. Continuity should exist. 
5. Check harness continuity between the following terminals and ground. See Fig 1.

   Refer to Wiring Diagram.

   1. Continuity should not exist. 
6. Check harness continuity between HO2S1 terminal 4 and ground.
   1. Continuity should exist. 
7. Also check harness for short to power.

OK or NG 

OK: GO TO 5. CHECK FUEL PRESSURE .

NG: GO TO 4.