Diagnosis Procedure

WARNING: This page is about a different car, the 2019 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.

CHECK CONNECTOR
1. Turn the ignition switch OFF.
2. Disconnect the battery cable from the negative terminal.
3. Check the following terminals and connectors for damage, bend and loose connection (unit side and connector side).
  - TCU
  - 3CH CAN gateway
Is the inspection result normal?

YES

GO TO 2.

NO

Repair the terminal and connector.

CHECK HARNESS CONTINUITY (OPEN CIRCUIT)

Disconnect the connector of 3CH CAN gateway.

Check the continuity between the 3CH CAN gateway harness connector terminals.

3CH CAN gateway harness connector			Continuity
Connector No.	Terminal No.
M6	9	13	Existed
	10	14	Existed

Is the inspection result normal?

YES

GO TO 3.

Check the harness and repair the root cause (IT CAN communication circuit side).

CHECK HARNESS FOR OPEN CIRCUIT

Connect the connector of 3CH CAN gateway.
Disconnect the connector of TCU.

Check the resistance between the TCU harness connector terminals.

TCU harness connector			Resistance (Ohm)
Connector No.	Terminal No.
M47	6	7	Approx. 54 - 66

Is the measurement value within the specification?

YES

GO TO 4.

Repair the TCU branch line.

CHECK POWER SUPPLY AND GROUND CIRCUIT
Check the power supply and the ground circuit of the TCU. Refer to Diagnosis Procedure .

Is the inspection result normal?

YES

Replace the TCU. Refer to Removal and Installation .

YES

Error was detected in the TCU branch line.

NO

Repair the power supply and the ground circuit.