Diagnostic Procedure

Check Ground Connections
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. See Figure .
Refer to GROUND INSPECTION .

OK or NG
1. OK: go to 2 .
2. NG: Repair or replace ground connections.
Retighten Heated Oxygen Sensor 1
Loosen and retighten heated oxygen sensor 1. See Figure .
1. Tightening torque: 45 N.m (4.6 kg-m, 33 ft-lb)
2. Go to 3 .
Check For Exhaust Gas Leak
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
  
  Fig 1: Identifying Exhaust System Components, Exhaust Gas Flow Direction & Possible Leak Locations
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: go to 4 .
2. NG: Repair or replace.
Check For Intake Air Leak
Listen for an intake air leak after the mass air flow sensor.

OK or NG
1. OK: go to 5 .
2. NG: Repair or replace.
Clear The Self-Learning Data
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II.
3. Clear the self-learning control coefficient by touching CLEAR.
4. Run engine for at least 10 minutes at idle speed.
  Is the 1st trip DTC P0171 or P0172 detected?
  
  Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness connector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
  Is the 1st trip DTC P0171 or P0172 detected?
  
  Is it difficult to start engine?
  
  For mass air flow sensor & intake air temperature sensor location, see Figure .
Yes or No
1. Yes: Perform trouble diagnosis for DTC P0171 or DTC P0172 Refer to DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION or DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION ).
2. No: go to 6 .
Check HO2S1 Ground Circuit For Open And Short
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 1 harness connector. See Figure .
3. Disconnect ECM harness connector.
4. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78.
  Refer to wiring diagram. See Figure Or Figure .
  1. Continuity should exist .
5. Also check harness for short to ground and short to power.
OK or NG
1. OK: go to 7 .
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. Refer to wiring diagram. See Figure Or Figure .
  
  Fig 3: Identifying ECM & Sensor Terminals W/Bank Locations For DTC P0133 & P0153 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 3 . Refer to wiring diagram. See Figure Or 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 8 .
  2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Check Mass Air Flow Sensor
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: go to 9 .
2. NG: Replace mass air flow sensor.
Check PCV Valve
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: go to 10 .
2. NG: Replace PCV valve.
Check Heated Oxygen Sensor 1
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: go to 11 .
2. NG: Replace malfunctioning heated oxygen sensor 1.
Check Intermittent Incident
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. Inspection end