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.

RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to Removal and Installation (bank 2) , Removal and Installation (bank 1) .

GO TO 2.

CHECK EXHAUST GAS LEAK

Start engine and run it at idle.

Listen for an exhaust gas leak before three way catalyst 1.

Courtesy of NISSAN NORTH AMERICA, INC.

Is exhaust gas leak detected?

YES

Repair or replace.

GO TO 3.

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.

NO

GO TO 4.
CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
1. Clear the mixture ratio self-learning value. Refer to Description .
2. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine?

YES

Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to DTC Description or DTC Description .

NO

GO TO 5.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY

Disconnect A/F sensor 1 harness connector.
Turn ignition switch ON.

Check the voltage between A/F sensor 1 harness connector and ground.

DTC	A/F sensor 1			Ground	Voltage
	Bank	Connector	Terminal
P014C P014D P015A P015B	1	F12	1	Ground	Battery voltage
P014E P014F P015C P015D	2	F61	1

Is the inspection result normal?

YES

GO TO 7.

GO TO 6.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

Turn ignition switch OFF.
Disconnect IPDM E/R harness connector.
Check the continuity between A/F sensor 1 harness connector and IPDM E/R harness connector.

DTC	A/F sensor 1			IPDM E/R		Continuity
DTC	Bank	Connector	Terminal	Connector	Terminal	Continuity
P014C P014D P015A P015B	1	F12	1	F50	52	Existed
P014E P014F P015C P015D	2	F61	1	F50	53	Existed

Is the inspection result normal?

YES

Perform the trouble diagnosis for power supply circuit.

Repair or replace error-detected parts.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

Turn ignition switch OFF.
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
P014C P014D P015A P015B	1	F12	3	F14	66	Existed
			4		67
P014E P014F P015C P015D	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
P014C P014D P015A P015B	1	F12	3	Ground	Not existed
			4
P014E P014F P015C P015D	2	F61	3
			4

DTC	ECM			Ground	Continuity
	Bank	Connector	Terminal
P014C P014D P015A P015B	1	F14	66	Ground	Not existed
			67
P014E P014F P015C P015D	2		76
			77

Also check harness for short to power.

Is the inspection result normal?

YES

GO TO 8.

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

CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Check air fuel ratio (A/F) sensor 1 heater. Refer to Component Inspection .

Is the inspection result normal?

YES

GO TO 9.

NO

Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to Removal and Installation (bank 2) , Removal and Installation (bank 1) .
CHECK MASS AIR FLOW SENSOR
Check both mass air flow sensor (bank 1 and bank 2). Refer to Component Inspection .

Is the inspection result normal?

YES

GO TO 10.

NO

Replace malfunctioning mass air flow sensor. Refer to Removal and Installation .
CHECK PCV VALVE
Check PCV valve. Refer to Work Procedure .

Is the inspection result normal?

YES

INSPECTION END

NO

Repair or replace PCV valve. Refer to Component Parts Location .