Diagnosis Procedure

WARNING: This page is about a different car, the 2018 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

CHECK EXHAUST GAS LEAKAGE

Start engine and run it at idle.

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.

GO TO 2.

CHECK FOR INTAKE AIR LEAKAGE
Listen for an intake air leakage after the mass air flow sensor.

Is intake air leakage detected?

YES

Repair or replace malfunctioning part.

NO

GO TO 3.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

Turn ignition switch OFF.
Disconnect corresponding A/F sensor 1 harness connector.
Disconnect ECM harness connector.

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	F12	3	F14	66	Existed
			4		67
P0175	2	F61	3		76
			4		77

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
P0172	1	F12	3	Ground	Not existed
			4
P0175	2	F61	3
			4

DTC	ECM		Ground	Continuity
	Connector	Terminal
P0172	F14	66	Ground	Not existed
		67
P0175		76
		77

Also check harness for short to power.

Is the inspection result normal?

YES

GO TO 4.

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

CHECK FUEL PRESSURE

Release fuel pressure to zero. Refer to Work Procedure .

Install fuel pressure gauge kit [SST: - (J-44321)] and check fuel pressure. Refer to Work Procedure .

At idling: Approximately 350 kPa (3.5 bar, 3.57 kg/cm ² , 51 psi)

Is the inspection result normal?

YES

GO TO 5.

Replace "fuel filter and fuel pump assembly". Refer to Removal and Installation .

CHECK MASS AIR FLOW SENSOR
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 6.

NO

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

CHECK FUNCTION OF FUEL INJECTOR

With CONSULT

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

With GST

Let engine idle.

Listen to each fuel injector operating sound.

Courtesy of NISSAN NORTH AMERICA, INC.

Is the inspection result normal?

YES

GO TO 7.

Perform trouble diagnosis for FUEL INJECTOR, refer to Diagnosis Procedure .

CHECK FUEL INJECTOR
1. Remove fuel injector assembly. Refer to Removal and Installation .
  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 injectors.
6. Crank engine for about 3 seconds.
  Check fuel does not drip from fuel injector.
Is the inspection result normal?

YES

INSPECTION END

NO

Replace the fuel injectors from which fuel is dripping. Always replace O-ring with new one. Refer to Removal and Installation .