4. Check HO2S2 Input Signal Circuit For Open And Short

1. Check harness continuity between ECM terminal and HO2S2 terminal as follows.

   Refer to WIRING DIAGRAM.

   Fig 1: Check Harness Continuity Between ECM Terminal And HO2S2 Terminals

   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 2: Check Harness Continuity Between The Following Terminals And Ground

   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.