Diagnostic Test

1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before three way catalyst (manifold).

   Courtesy of NISSAN NORTH AMERICA, INC.

Is exhaust gas leakage detected?

YES 

Repair or replace malfunctioning part.

NO 

GO TO STEP 2  .

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

Is intake air leakage detected?

YES 

Repair or replace malfunctioning part.

NO 

GO TO STEP 3  .

1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

   DTC	A/F sensor 1			ECM		Continuity
   	Bank	Connector	Terminal	Connector	Terminal
   P0171	1	F72	3	F79	66	Existed
   			4		67
   P0174	2	F73	3		76
   			4		77

5. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

   DTC	A/F sensor 1			Ground	Continuity
   	Bank	Connector	Terminal
   P0171	1	F72	3	Ground	Not existed
   			4
   P0174	2	F73	3
   			4

   DTC	ECM		Ground	Continuity
   	Connector	Terminal
   P0171	F79	66	Ground	Not existed
   		67
   P0174		76
   		77

6. Also check harness for short to power.

Is the inspection result normal?

YES 

GO TO STEP 4  .

NO 

Repair open circuit, short to ground or short to power in harness or connectors.

1. Release fuel pressure to zero. Refer to WORK PROCEDURE .
2. Install fuel pressure gauge kit [SST: - (J-44321)] and check fuel pressure. Refer to WORK PROCEDURE .

   At idling: Approximately 350 kPa (3.57 kg/cm2 , 51 psi)

Is the inspection result normal?

YES 

GO TO STEP 6  .

NO 

GO TO STEP 5  .

Check fuel hoses and fuel tubes for clogging.

Is the inspection result normal?

YES 

Replace "fuel filter and fuel pump assembly". Refer to REMOVAL AND INSTALLATION .

NO 

Repair or replace malfunctioning part.

With CONSULT 

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

   For specification, refer to MASS AIR FLOW SENSOR .

With GST 

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

   For specification, refer to MASS AIR FLOW SENSOR .

Is the measurement value within the specification?

YES 

GO TO STEP 7  .

NO 

Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DIAGNOSIS PROCEDURE .

With CONSULT 

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

With GST 

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

   Courtesy of NISSAN NORTH AMERICA, INC.

Is the inspection result normal?

YES 

GO TO STEP 8  .

NO 

Perform trouble diagnosis for FUEL INJECTOR, refer to DIAGNOSIS PROCEDURE .

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 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.

Is the inspection result normal?

YES 

Check intermittent incident. Refer to INTERMITTENT INCIDENT .

NO 

Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones. Refer to REMOVAL AND INSTALLATION .