DTC Diagnosis Procedure

WARNING: This page is about a different car, the 2020 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.

CHECK GROUND CONNECTION
1. Turn ignition switch OFF.
2. Check ground connection E9. Refer to Circuit Inspection .
Is the inspection result normal?

YES

GO TO 2.

NO

Repair or replace ground connection.

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

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

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

A/F sensor 1		Ground	Voltage
Connector	Terminal
F72	1	Ground	Battery voltage

Is the inspection result normal?

YES

GO TO 4.

GO TO 3.

DETECT MALFUNCTIONING PART
Check the following.
- IPDM E/R harness connector F19
- 15 A fuse (No. 40)
- Harness for open or short between A/F sensor 1 and fuse
Repair or replace harness or connectors.

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.

A/F sensor 1		ECM		Continuity
Connector	Terminal	Connector	Terminal
F72	3	F79	102	Existed
	4		101

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

A/F sensor 1		Ground	Continuity
Connector	Terminal
F72	3	Ground	Not existed
	4

ECM		Ground	Continuity
Connector	Terminal
F79	102	Ground	Not existed
	101

Also check harness for short to power.

Is the inspection result normal?

YES

GO TO 5.

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

CHECK INTERMITTENT INCIDENT
Refer to Intermittent Incident .

Is the inspection result normal?

YES

GO TO 6.

NO

Repair or replace.
REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1.
CAUTION:
- Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new A/F sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved Anti-seize Lubricant (commercial service tool).
INSPECTION END