Diagnostic Procedure

1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
   Fig 1: Checking Exhaust Gas Leak

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

OK or NG 

1. OK: GO TO 2.
2. NG: Repair or replace.

1. Listen for an intake air leak between the mass air flow sensor and the intake manifold.
2. Check PCV hose connection.

OK or NG 

1. OK: GO TO 3.
2. NG: Repair or replace.

1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 1 harness connector and ECM harness connector.
3. Check harness continuity between ECM terminal 50 and HO2S1 terminal 2.

   Refer to WIRING DIAGRAM .

   Continuity should exist. 

4. Check harness continuity between ECM terminal 50 or HO2S1 terminal 2 and ground.

   Refer to WIRING DIAGRAM .

   Continuity should not exist. 

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

Fig 2: Checking Harness Continuity Between ECM Terminal Or HO2S1 Terminal And Ground

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

OK or NG 

1. OK: GO TO 4.
2. 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 RELEASE .

2. Install fuel pressure gauge and check fuel pressure.

   At idling 

   When fuel pressure regulator valve vacuum hose is connected. 235 kPa (2.4 kg/cm ² , 34 psi)

   When fuel pressure regulator valve vacuum hose is disconnected. 294 kPa (3.0 kg/cm ² , 43 psi)

   OK or NG 

1. OK: GO TO  6.
2. NG: GO TO 5.

Check the following.

• Fuel pump and circuit (Refer to FUEL PUMP CIRCUIT .)
• Fuel pressure regulator (Refer to FUEL PRESSURE REGULATOR CHECK .)
• Fuel lines (Refer to "CHANGING FUEL FILTER ".)
• Fuel filter for clogging
  1. Repair or replace.

Refer to COMPONENT INSPECTION .

OK or NG 

1. OK: GO TO 7.
2. NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or engine grounds. Refer to DTC P0102, P0103 MAF SENSOR .

With CONSULT-II 

1. Install all parts removed.
2. Start engine.
3. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-II.
4. Make sure that each circuit produces a momentary engine speed drop.

Fig 3: Scan Tool Display - Active Test

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

Without CONSULT-II 

1. Install all parts removed.
2. Start engine.
3. Listen to each injector operating sound.

   Clicking noise should be heard. 

OK or NG 

1. OK: GO TO 8.
2. NG: Perform trouble diagnosis for injector, refer to INJECTOR CIRCUIT .

Fig 4: Checking Clicking Noise

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

1. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
2. Turn ignition switch OFF.
3. Remove injector with fuel tube assembly.

   Keep fuel hose and all injectors connected to injector gallery. The injector harness connectors should remain connected.

   1. GO TO 9.

Refer to COMPONENT INSPECTION .

OK or NG 

1. OK: GO TO 10.
2. NG: Replace injectors from which fuel does not spray out. Always replace O-ring with new one.

Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

1. : INSPECTION END.