Diagnosis 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 NORTH AMERICA, INC.

   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 corresponding A/F sensor 1 harness connector.
   Fig 2: Identifying A/F Sensor 1 Harness Connector

   Courtesy of NISSAN NORTH AMERICA, INC.
3. Disconnect ECM harness connector.
4. Check harness continuity between A/F sensor 1 terminal and ECM terminal as follows.

   Refer to WIRING DIAGRAM .

   TERMINAL CONTINUITY REFERENCE CHART
   
   

   -	A/F sensor 1 terminal	ECM terminal
   Bank 1	1	35
   	2	56
   Bank 2	1	16
   	2	75

   Continuity should exist. 

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

   Refer to WIRING DIAGRAM .

   TERMINAL CONTINUITY REFERENCE CHART
   
   

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

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

   OK or NG 

   OK (With CONSULT-III): GO TO  6.

   OK (Without CONSULT-III): GO TO  7.

   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
• Fuel filter for clogging

  Repair or replace.

With CONSULT-III 

1. Install all removed parts.
2. Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT-III.

   2.0 - 6.0 g/s: at idling 

   7.0 - 20.0 g/s: at 2, 500 rpm 

   OK or NG 

   OK: GO TO  8.

   NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "COMPONENT DESCRIPTION ".

With GST 

1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.

   2.0 - 6.0 g/s: at idling 

   7.0 - 20.0 g/s: at 2, 500 rpm 

   OK or NG 

   OK (P0171): GO TO  9.

   OK (P0174): GO TO  11.

   NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "COMPONENT DESCRIPTION ".

With CONSULT-III 

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

   OK or NG 

   OK: GO TO  12.

   NG: Perform trouble diagnosis for FUEL INJECTOR, refer to "COMPONENT DESCRIPTION ".

Without CONSULT-III 

1. Stop engine.
2. Disconnect harness connector F44 (3), F201 (1)
   Fig 3: Identifying Harness Connector F44, F201 And Vacuum Tank

   Courtesy of NISSAN NORTH AMERICA, INC.
3. Turn ignition switch ON.
4. Check voltage between harness connector F44 terminal 3 and ground with CONSULT-III or tester.
   Fig 4: Checking Voltage Between Harness Connector F44 Terminal 3 And Ground

   Courtesy of NISSAN NORTH AMERICA, INC.

   Voltage: Battery voltage 

5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between harness connector F44 and ECM as follows.

   Refer to WIRING DIAGRAM .

   TERMINAL CONTINUITY REFERENCE CHART
   
   

   Cylinder	Harness connector F44 terminal	ECM terminal
   1	2	23
   3	1	22
   5	4	21

   Continuity should exist. 

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

   OK or NG 

   OK: GO TO 10.

   NG: Perform trouble diagnosis for FUEL INJECTOR, refer to FUEL INJECTOR .

Provide battery voltage between harness connector F201 as follows and then interrupt it. Listen to each fuel injector operating sound.

Operating sound should exist. 

Fig 5: Applying Battery Voltage Between Harness Connector F201

Courtesy of NISSAN NORTH AMERICA, INC.

OK or NG 

OK: GO TO  12.

NG: Perform trouble diagnosis for FUEL INJECTOR, refer to FUEL INJECTOR .

1. Start engine.
2. Listen to fuel injectors No. 2, No. 4, No. 6 operating sound.

   Clicking noise should exist. 

   Fig 6: Checking Fuel Injector Operating Sound

   Courtesy of NISSAN NORTH AMERICA, INC.

   OK or NG 

   OK: GO TO 12.

   NG: Perform trouble diagnosis for FUEL INJECTOR, refer to FUEL INJECTOR .

1. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
2. Turn ignition switch OFF.
3. Disconnect all injector harness connectors.
4. Remove fuel tube assembly. Refer to "REMOVAL AND INSTALLATION ".

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

5. For DTC P0171, reconnect fuel injector harness connectors on bank 1.

   For DTC P0174, reconnect fuel injector harness connectors on bank 2.

6. Disconnect all ignition coil harness connectors.
7. Prepare pans or saucers under each fuel injector.
8. Crank engine for about 3 seconds.

   For DTC P0171, check that fuel sprays out from fuel injectors on bank 1.

   For DTC P0174, check that fuel sprays out from fuel injectors on bank 2.

   Fuel should be sprayed evenly for each fuel injector. 

   Fig 7: Checking Fuel Injector Spray

   Courtesy of NISSAN NORTH AMERICA, INC.

   OK or NG 

   OK: GO TO 13.

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

Refer to "INTERMITTENT INCIDENT ".

INSPECTION END