Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.

   Refer to "GROUND INSPECTION ".

   Fig 1: Checking Ground Connections

   Courtesy of NISSAN NORTH AMERICA, INC.

OK or NG 

OK: GO TO 2.

NG: Repair or replace ground connections.

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 P0174 detected? 

   Is it difficult to start engine? 

   Fig 2: CONSULT-II Display - "DATA MONITOR"

   Courtesy of NISSAN NORTH AMERICA, INC.

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 P0174 detected? 

   Is it difficult to start engine? 

   Fig 3: Identifying Mass Air Flow (MAF) Sensor Harness Connector

   Courtesy of NISSAN NORTH AMERICA, INC.

Yes or No 

Yes: Perform trouble diagnosis for DTC P0171 or P0174. Refer to "DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION ".

No: GO TO 3.

1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector.
   Fig 4: Identifying Heated Oxygen Sensor 2 Harness Connector

   Courtesy of NISSAN NORTH AMERICA, INC.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4.

   Refer to WIRING DIAGRAM .

   Continuity should exist. 

5. Also check harness for short to ground and short to power.

OK or NG 

OK: GO TO 4.

NG: Repair open circuit or short to ground or short to power in harness or connectors.

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

   Refer to WIRING DIAGRAM .

   TERMINALS REFERENCE
   
   

   DTC	Terminals		Bank
   	ECM	Sensor
   P0137	55	1	1
   P0157	74	1	2

   Continuity should exist. 

2. Check harness continuity between the following terminals and ground.

   Refer to WIRING DIAGRAM .

   TERMINALS REFERENCE
   
   

   DTC	Terminals		Bank
   	ECM	Sensor
   P0137	55	1	1
   P0157	74	1	2

   Continuity should not exist. 

3. 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 malfunctioning heated oxygen sensor 2.

Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

INSPECTION END