Diagnostic Procedure

Check Ground Connections
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body, See Figure and Refer to GROUND INSPECTION .
OK or NG
1. OK: go to 2 .
2. NG: Repair or replace ground connections.
Check HO2S1 Ground Circuit For Open And Short
1. Disconnect heated oxygen sensor 1 harness connector. See Figure .
2. Disconnect ECM harness connector.
3. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78.
  Refer to wiring diagram. See Figure and Figure .
  1. Continuity should exist .
4. Also check harness for short to ground and 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 HO2S1 Input Signal Circuit For Open And Short
1. Check harness continuity between ECM terminal and HO2S1 terminal as follows, see Fig 1 . Refer to wiring diagram. See Figure and Figure .
  
  Fig 1: Identifying ECM & Sensor Terminals W/Bank Locations For DTC P0134 & P0154 Testing
  Courtesy of NISSAN MOTOR CO., U.S.A.
  1. Continuity should exist .
2. Check harness continuity between the following terminals and ground. See Fig 1 .
  Refer to wiring diagram. See Figure and Figure .
  1. Continuity should not exist .
3. 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.
CHECK HEATED OXYGEN SENSOR 1
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: go to 5 .
2. NG: Replace malfunctioning heated oxygen sensor 1.
Check Intermittent Incident
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

Inspection end