Diagnosis Procedure

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

CHECK DTC PRIORITY
1. Turn ignition switch ON.
2. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
3. Check for DTC P0629-00 being current on the CONSULT screen.
Is DTC P0629-00 detected as current?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT LIFT PUMP RELAY AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector E122.
3. Inspect the engine harness and IPDM E/R connector pins for the following:
  - Loose connector
  - Corroded pins
  - Bent or broken pins
  - Pushed back or expanded pins
  - Moisture in or on the connector
  - Missing or damaged connector seals
  - Dirt or debris on or in the connector pins
  - Connector shell broken
  - Wire insulation damage
  - Damaged connector locking tab.
Is the inspection result normal?

YES

GO TO 3 .

NO

Repair or replace error-detected parts.
INSPECT ECM AND HARNESS CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector E93.
3. Inspect the ECM connector pins for the following:
  - Loose connector
  - Corroded pins
  - Bent or broken pins
  - Pushed back or expanded pins
  - Moisture in or on the connector
  - Missing or damaged connector seals
  - Dirt or debris on or in the connector pins
  - Connector shell broken
  - Wire insulation damage
  - Damaged connector locking tab.
Is the inspection result normal?

YES

GO TO 4 .

NO

Repair or replace error-detected parts.

CHECK FOR AN OPEN CIRCUIT IN THE HARNESS

Turn ignition switch OFF.
Disconnect the ECM harness connector E93.
Disconnect the IPDM E/R harness connector E122.

Measure the resistance between the ECM harness connector E93 terminal 40 and the IPDM E/R harness connector E122 terminal 45.

ECM		IPDM E/R		Resistance
Connector	Terminal	Connector	Terminal	Resistance
E93	40	E122	45	< 10 Ω

Is the inspection result normal?

YES

GO TO 5 .

Repair or replace the engine harness for an open.

CHECK FOR A SHORT CIRCUIT TO VOLTAGE IN THE HARNESS

Measure the resistance between ECM harness connector E93 terminal 40 and battery positive terminal.

ECM		Battery positive	Resistance
Connector	Terminal
E93	40	+	> 100k Ω

Is the inspection result normal?

YES

GO TO 6 .

Repair or replace the harness for a short to voltage

CHECK FOR A PIN-TO-PIN SHORT CIRCUIT IN THE HARNESS

Turn ignition switch OFF.
Disconnect the ECM harness connector E93.
Disconnect the IPDM E/R harness connector E122.

Measure the resistance between the ECM harness connector E93 terminal 40 and all other terminals in the ECM harness connector E93.

ECM		ECM		Resistance
Connector	Terminal	Connector	Terminal	Resistance
E93	40	E93	All	> 100k Ω

Is the inspection result normal?

YES

GO TO 7 .

Repair or replace the harness for a short.

CHECK PAST DTC
1. Connect all components.
2. Turn ignition switch ON.
3. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
4. Check for DTC P0629-00 being past on the CONSULT screen.
Is the inspection result normal?

YES

The removal and installation of the connector corrected the issue.

NO

Replace the ECM. Refer to Removal and Installation .