Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten engine two screws on the body.
  Refer to "GROUND INSPECTION ".
  
  Fig 1: Locating ECM Ground Screws On Body
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 2.
2. NG : Repair or replace ground connections.
RETIGHTEN AIR FUEL RATIO (A/F) SENSOR 1
Loosen and retighten the air fuel ratio (A/F) sensor 1.

Fig 2: Locating Air Fuel Ratio (A/F) Sensor 1
Courtesy of NISSAN MOTOR CO., U.S.A.
1. Tightening torque: 40 - 60 N-m (4.1 - 6.1 kg-m, 30 - 44 ft-lb)
2. : GO TO 3.
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.
  
  Fig 3: WORK SUPPORT, SELF-LEARNING CONT - CONSULT-II Display Screen
  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 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.
  
  Fig 4: Identifying Mass Air Flow Sensor
  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 P0172 detected? Is it difficult to start engine?
Yes or No
1. Yes : Perform trouble diagnosis for DTC P0172. Refer to DTC P0172 FUEL INJECTION SYSTEM FUNCTION .
2. No : GO TO 4.
CHECK HARNESS CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
  
  Fig 5: Disconnecting A/F Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check harness connector for water.
  Water should not exit.
OK or NG
1. OK : GO TO 5.
2. NG : Repair or replace harness connector.
CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
2. Check voltage between A/F sensor 1 terminal 3 and ground with CONSULT-II or tester.
  1. Voltage: Battery voltage
OK or NG
1. OK : GO TO 7.
2. NG : GO TO 6.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M19, E108
- Harness connectors E10, F48
- Fuse block (J/B) connector M1
- 15A fuse
- Harness for open or short between A/F sensor 1 and fuse
  1. : Repair or replace harness or connectors.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

Turn ignition switch OFF.
Disconnect ECM harness connector.

Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .

ECM TERMINALS AND A/F SENSOR 1 TERMINALS REFERENCE

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

Continuity should exist.

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 .
1. Continuity should not exist.
Also check harness for short to power.

OK or NG

OK : GO TO 8.
NG : Repair open circuit or short to ground or short to power in harness or connectors.

CHECK A/F SENSOR 1 HEATER
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK : GO TO 9.
2. NG : Replace A/F sensor 1.
CHECK INTERMITTENT INCIDENT
Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

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