1.CHECK EXHAUST GAS LEAK

1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst 1.

Is exhaust gas leak detected?
YES>>Repair or replace malfunctioning part.
NO>>GO TO 2.
2.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected?
YES>>Repair or replace malfunctioning part.
NO>>GO TO 3.
3.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

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
   P0172 | 1 | F8 | 1 | F102 | 81 | Existed
   2 | 82
   P0175 | 2 | F25 | 1 | 85
   2 | 86

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

   DTC | A/F sensor 1 | ECM | Ground | Continuity
   Bank | Connector | Terminal | Connector | Terminal
   P0172 | 1 | F8 | 1 | F102 | 81 | Ground | Not existed
   2 | 82
   P0175 | 2 | F25 | 1 | 85
   2 | 86

6. Also check harness for short to power.

Is the inspection result normal?
YES>>GO TO 4.
NO>>Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK FUEL PRESSURE
Check fuel pressure. Refer to Inspection (GT-R certified NISSAN dealer).
Is the inspection result normal?
YES>>GO TO 5.
NO>>Replace “fuel filter and fuel pump assembly”.
5.CHECK MASS AIR FLOW SENSOR
With CONSULT-III

1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.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 6.
NO>>Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to Diagnosis Procedure (GT-R certified NISSAN dealer).
6.CHECK FUNCTION OF FUEL INJECTOR
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.

Without CONSULT-III

1. Start engine and let it idle.
2. Listen to each fuel injector operating sound.

   Clicking sound should be heard.

Is the inspection result normal?
YES>>GO TO 7.
NO>>Perform trouble diagnosis for FUEL INJECTOR, refer to Diagnosis Procedure (GT-R certified NISSAN dealer).
7.CHECK FUEL INJECTOR

1. Remove fuel injector assembly. Refer to Removal and Installation (GT-R certified NISSAN dealer).Keep fuel hose and all fuel injectors connected to fuel tube.
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. Disconnect all ignition coil harness connectors.
5. Prepare pans or saucers under each fuel injector.
6. Crank engine for about 3 seconds.Check that fuel does not drip from fuel injector.

Is the inspection result normal?
YES>>GO TO 8.
NO>>Replace the fuel injectors from which fuel is dripping. Always replace O-ring with new one.
8.CHECK INTERMITTENT INCIDENT
Refer to Intermittent Incident.
>>INSPECTION END