Diagnosis Procedure

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

CHECK DIFFERENTIAL LOCK SOLENOID POWER SUPPLY VOLTAGE

Turn the ignition switch OFF.

Check the voltage between differential lock control unit harness connector and ground.

Differential lock control unit

Voltage

(Approx.)

Connector

Terminal

B77

Ground

Battery voltage

Turn the ignition switch ON.
CAUTION: Never start the engine.

Check the voltage between differential lock control unit harness connector and ground.

Differential lock control unit

Voltage

(Approx.)

Connector

Terminal

B77

Ground

Battery voltage

Is the inspection result normal?

YES

GO TO STEP 3 .

GO TO STEP 2 .

CHECK DIFFERENTIAL LOCK SOLENOID POWER SUPPLY CIRCUIT

Turn the ignition switch OFF.
Check the 10 A (No. 64).
Disconnect fusible link box LH harness connector. Refer to SYSTEM WIRING DIAGRAMS .

Check the continuity between differential lock control unit harness connector and ground.

Differential lock control unit		Fusible link box LH		Continuity
Connector	Terminal	Connector	Terminal
B77	9	E27 (Cummins 5.0L)	1	Yes
		E148 (VK56VD)	3

Check the continuity between differential lock control unit harness connector and the ground.

Differential lock control unit		-	Continuity
Connector	Terminal
B77	9	Ground	No

Is the inspection result normal?

YES

Perform the trouble diagnosis for power supply circuit. Refer to SYSTEM WIRING DIAGRAMS .

Repair or replace the malfunctioning parts.

CHECK DIFFERENTIAL LOCK CONTROL UNIT GROUND

Turn the ignition switch OFF.

Check the continuity between differential lock control unit harness connector and ground.

Differential lock control unit		-	Continuity
Connector	Terminal
B77	10	Ground	Yes
	11

Is the inspection result normal?

YES

GO TO STEP 4 .

Repair or replace the malfunctioning parts.

CHECK DIFFERENTIAL LOCK SOLENOID CIRCUIT

Check the resistance between differential lock control unit harness connector.

Differential lock control unit			Resistance (Approx.)
Connector	Terminal
B77	1	2	3.8 Ω

Is the inspection result normal?

YES

GO TO STEP 6 .

GO TO STEP 5 .

CHECK HARNESS FOR DIFFERENTIAL LOCK SOLENOID CIRCUIT

Remove differential lock solenoid harness connector.

Check the continuity between differential lock control unit harness connector and differential lock solenoid harness connector.

Differential lock control unit		Differential lock solenoid		Continuity
Connector	Terminal	Connector	Terminal
B77	1	C17	1	Yes
	2		2

Check the continuity between differential lock control unit harness connector and the ground.

Differential lock control unit		-	Continuity
Connector	Terminal
B77	1	Ground	No
	2

Is the inspection result normal?

YES

GO TO STEP 6 .

Repair or replace the malfunctioning parts.

CHECK DIFFERENTIAL LOCK SOLENOID
Check differential lock solenoid. Refer to Component Inspection .

Is the inspection result normal?

YES

GO TO STEP 7 .

NO

Differential lock solenoid is malfunctioning. Replace differential assembly. Refer to Disassembly and Assembly .
CHECK TERMINALS AND HARNESS CONNECTORS
- Check differential lock control unit pin terminals for damage or loose connection with harness connector.
- Check differential lock solenoid pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?

YES

After erasing the DTC, perform DTC confirmation procedure again. If DTC "P1849" is detected, replace differential lock control unit. Refer to Removal and Installation .

NO

Repair or replace the malfunctioning parts.