Diagnostic Procedure

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

   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 corresponding air fuel ratio (A/F) sensor 1 harness connector.
   Fig 2: Identifying Corresponding 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 Wiring Diagram.
   TERMINALS REFERENCE
   
   

   	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 Wiring Diagram.
   TERMINALS REFERENCE
   
   

   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 RELEASE ".
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 : 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 "CHECKING FUEL LINES ".)
• Fuel filter for clogging

  : Repair or replace.

With CONSULT-II 

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

   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. 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-II) : GO TO 7.

OK (Without CONSULT-II) : GO TO  8.

NG : Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to "DTC P0102, P0103 MAF SENSOR ".

With CONSULT-II 

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

OK or NG 

OK : GO TO  10.

NG : Perform trouble diagnosis for "FUEL INJECTOR ".

Fig 3: Consult-II ACTIVE TEST Display Screen

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

Without CONSULT-II 

1. Turn ignition switch OFF.
2. Disconnect harness connectors F21, F201 (bank 1) and F41, F221 (bank 2).
   Fig 4: Identifying Harness Connectors F21, F201 (Bank 1) And F41, F221 (Bank 2)

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Turn ignition switch ON.
4. Check voltage between the following; harness connector F21 terminal 5 and ground, harness connector F41 terminal 5 and ground with CONSULT-II or tester.

   Voltage: Battery voltage 

   Fig 5: Identifying Voltage Between Harness Connector F21 Terminal 5, Harness Connector F41 Terminal 5 And Ground

   Courtesy of NISSAN MOTOR CO., U.S.A.
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between the following terminals.
   TERMINALS REFERENCE
   
   

   Cylinder	Harness connector terminal	ECM terminal
   1	F21 terminal 3	23
   3	F21 terminal 2	22
   5	F21 terminal 1	21
   7	F21 terminal 6	44
   2	F41 terminal 3	42
   4	F41 terminal 2	41
   6	F41 terminal 1	40
   8	F41 terminal 6	63

   Continuity should exist. 

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

OK or NG 

OK : GO TO 9.

NG : Perform trouble diagnosis for "FUEL INJECTOR ".

Provide battery voltage between the following terminals, and then interrupt it. Listen to each fuel injector operating sound.

Fig 6: Identifying Function Of Fuel Injector-II

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

Operating sound should exist. 

OK or NG 

OK : GO TO 10.

NG : Perform trouble diagnosis for "FUEL INJECTOR ".

1. Turn ignition switch OFF.
2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
3. Disconnect all fuel injector harness connectors.
4. Remove fuel tube assembly. Refer to "FUEL INJECTOR AND FUEL TUBE ". 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, make sure that fuel sprays out from fuel injectors on bank 1.

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

   Fuel should be sprayed evenly for each fuel injector. 

   Fig 7: Identifying Fuel Injector

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

OK or NG 

OK : GO TO 11.

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

Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

: INSPECTION END