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 

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: Disconnecting Corresponding 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.
   A/F SENSOR AND ECM TERMINALS REFERENCE (1 OF 2)
   
   

   	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.
   A/F SENSOR AND ECM TERMINALS REFERENCE (2 OF 2)
   
   

   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: Approximately 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 RELEASE .")
• Fuel lines (Refer to "CHECKING 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.m/sec: at idling 

   7.0 - 20.0 g.m/sec: 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 "DTC P0101 MAF SENSOR ."

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 (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 "DTC P0101 MAF SENSOR ."

With CONSULT-III 

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

OK or NG 

OK: GO TO  12.

NG: Perform trouble diagnosis for "FUEL INJECTOR ."

Without CONSULT-III 

1. Stop engine.
2. Disconnect harness connector F44 (1), F101 (2).
   • ← : Vehicle front
   • Intake manifold collector (3)
3. Turn ignition switch ON.
   Fig 3: Identifying Harness Connector And Manifold Collector

   Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between harness connector F44 terminal 5 and ground with CONSULT-III or tester.

   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.

   HARNESS CONNECTOR F44 AND ECM
   
   

   Cylinder	Harness connector F44 terminal	ECM terminal
   1	6	23
   3	2	22
   5	1	21

   Fig 4: Checking Voltage Between Harness Connector F44 Terminal 5 And Ground

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

   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 ."

Provide battery voltage between harness connector F101 as follows and then interrupt it. Listen to each fuel injector operating sound.

Fig 5: Checking Function Of Fuel Injector-II

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

Operating sound should exist  .

OK or NG 

OK: GO TO  12.

NG: Perform trouble diagnosis for "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 Function Of Fuel Injector

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

OK or NG 

OK: GO TO  12.

NG: Perform trouble diagnosis for "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 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: Checking Fuel Injector

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

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 "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ."

>> INSPECTION END