Diagnosis Procedure

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

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

   OK or NG 

   OK: GO TO 2.

   NG: Repair or replace.

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

   OK or NG 

   OK: GO TO 3.

   NG: Repair or replace.

1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector (1).
   • Air fuel ratio (A/F) sensor 1 (2)
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals.

   Refer to WIRING DIAGRAM .

   CONTINUITY SPECIFICATION
   
   

   A/F sensor 1 terminal	ECM terminal
   1	49
   2	53

   Continuity should exist. 

   Fig 2: Identifying Air Fuel Ratio (A/F) Sensor 1 Harness Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.
5. Check harness continuity between ECM terminals 49, 53 or A/F sensor 1 terminals 1, 2 and ground.

   Refer to WIRING DIAGRAM .

   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 FUEL PUMP .)
• Fuel pressure regulator (Refer to "FUEL PRESSURE CHECK ".)
• Fuel lines (Refer to FUEL INJECTOR AND FUEL TUBE .)
• Fuel filter for clogging

  Repair or replace.

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.

   at idling : 1.0 - 4.0 g.m/sec 

   at 2, 500 RPM : 2.0 - 10.0 g.m/sec 

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.

   at idling : 1.0 - 4.0 g.m/sec 

   at 2, 500 RPM : 2.0 - 10.0 g.m/sec 

   OK or NG 

   OK: GO TO 7.

   NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DTC P0101 MAF SENSOR .

With CONSULT-III 

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

Without CONSULT-III 

1. Let engine idle.
2. Listen to each fuel injector operating sound.

   Clicking noise should be heard. 

   OK or NG 

   OK: GO TO 8.

   NG: Perform trouble diagnosis for FUEL INJECTOR .

   Fig 3: Checking Fuel Injector

   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. Reconnect all harness connectors disconnected.
4. Remove fuel tube assembly. Refer to FUEL INJECTOR AND FUEL TUBE .

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

   The fuel injector harness connectors should remain connected.

5. Disconnect all ignition coil harness connectors.
6. Prepare pans or saucers under each fuel injector.
7. Crank engine for about 3 seconds. Make sure that fuel sprays out from fuel injectors.

   Fuel should be sprayed evenly for each fuel injector. 

   OK or NG 

   OK: GO TO 9.

   NG: Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones.

   Fig 4: Checking Fuel Injector

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

Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

INSPECTION END