Diagnosis Procedure

1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before three way catalyst (manifold).

Fig 1: Checking Exhaust Gas Leakage

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

OK or NG 

OK: GO TO 2.

NG: Repair or replace malfunctioning part.

Listen for an intake air leakage after the mass air flow sensor.

OK or NG 

OK: GO TO 3.

NG: Repair or replace malfunctioning part.

1. Turn ignition switch OFF.
2. Disconnect corresponding air fuel ratio (A/F) sensor 1 harness connector.
   Fig 2: Identifying Air Fuel Ratio (A/F) Sensor 1 Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals.

   Refer to SYSTEM WIRING DIAGRAMS article.

   ECM CONNECTOR TERMINALS REFERENCE CHART
   
   

   	A/F sensor 1 terminal	ECM terminal
   Bank 1	1	16
   	2	75
   	5	35
   	6	56
   Bank 2	1	76
   	2	77
   	5	57
   	6	58

   Continuity should exist  .

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

   Refer to SYSTEM WIRING DIAGRAMS article.

   ECM CONNECTOR TERMINALS REFERENCE CHART
   
   

   Bank 1		Bank 2
   A/F sensor 1 terminal	ECM terminal	A/F sensor 1 terminal	ECM terminal
   1	16	1	76
   2	75	2	77
   5	35	5	57
   6	56	6	58

   Continuity should not exist  .

6. Also check harness for 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. Release fuel pressure to zero. Refer to "FUEL PRESSURE CHECK ".
2. Install fuel pressure gauge and check fuel pressure. Refer to "FUEL PRESSURE CHECK ".

   At idling: Approximately 350 kPa (3.57 kg/cm ²  , 51 psi) 

OK or NG 

OK: GO TO  6.

NG: GO TO 5.

Check the following.

• Fuel pump and circuit (Refer to "DIAGNOSIS PROCEDURE ".)
• Fuel pressure regulator (Refer to "FUEL PRESSURE CHECK ".)

  Repair or replace malfunctioning part.

With CONSULT-III 

1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT-III.

   2.0 - 6.0 g.m/sec: at idling 

   7.0 - 20.0 g.m/sec: at 2, 500 RPM 

With GST 

1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check mass air flow sensor signal in Service $01 with GST.

   2.0 - 6.0 g.m/sec: at idling 

   7.0 - 20.0 g.m/sec: at 2, 500 RPM 

OK or NG 

OK (With CONSULT-III): GO TO 7.

OK (Without CONSULT-III): GO TO  8.

NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to "DIAGNOSIS PROCEDURE ".

With CONSULT-III 

1. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-III.
2. Check that each circuit produces a momentary engine speed drop.

OK or NG 

OK: GO TO  9.

NG: Perform trouble diagnosis for fuel injector, refer to "DIAGNOSIS PROCEDURE ".

Without CONSULT-III 

Listen to fuel injector operating sound.

Operating sound should exist  .

OK or NG 

OK: GO TO 9.

NG: Perform trouble diagnosis for fuel injector, refer to "DIAGNOSIS PROCEDURE ".

Fig 3: Checking Fuel Injector Operating Sound

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

1. Remove fuel tube assembly. Refer to "COMPONENT ".

   Keep fuel hose and all fuel injectors connected to fuel tube.

2. Check that the engine is cooled down and there are no fire hazards near the vehicle.
3. Disconnect all fuel injector harness connectors.
4. Disconnect all ignition coil harness connectors.
5. Prepare pans or saucers under each fuel injector.
6. Crank engine for approximately 3 seconds.

Check that fuel does not drip from fuel injector.

OK or NG 

OK (Does not drip.): GO TO 10.

NG (Drips.): Replace the fuel injectors from which fuel is dripping. Always replace O-ring with new one.

Refer to "DIAGNOSIS PROCEDURE ".

INSPECTION END