Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten two ground screws on the body. Refer to "GROUND INSPECTION ".
   Fig 1: Identifying ECM Ground Screws On Body

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

OK or NG 

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

Loosen and retighten the air fuel ratio (A/F) sensor 1.

• Tightening torque: 40 - 60 N-m (4.1 - 6.1 kg-m, 30 - 44 ft-lb) 
• : GO TO 3.

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.
   Fig 2: CONSULT-II Display - WORK SUPPORT Mode

   Courtesy of NISSAN MOTOR CO., U.S.A.
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 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 3 seconds at idle speed.
   Fig 3: Disconnecting Mass Air Flow Sensor Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
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 detected? Is it difficult to start engine? 

Yes or No 

• Yes : Perform trouble diagnosis for DTC P0171. Refer to DTC P0171 FUEL INJECTION SYSTEM FUNCTION .
• No : GO TO 4.

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector and A/F sensor 1 harness connector.
   Fig 4: Disconnecting ECM Harness Connector And A/F Sensor

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .
   A/F SENSOR 1 & ECM TERMINAL CONTINUITY SPECIFICATION
   
   

   A/F sensor 1 terminal	ECM terminal
   1	16
   2	75
   5	35
   6	56

   • Continuity should exist. 
4. Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to WIRING DIAGRAM .
   • Continuity should not exist. 
5. Also check harness for short to power.

OK or NG 

• OK : GO TO 5.
• NG : Repair open circuit or short to ground or short to power in harness or connectors.

Refer to "COMPONENT INSPECTION ".

OK or NG 

• OK : GO TO 6.
• NG : Replace A/F sensor 1.

Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

OK or NG 

• OK : Replace A/F sensor 1.
• NG : Repair or replace.