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 P0521-00 being current on the CONSULT screen.
Is DTC P0521-00 detected as current?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT OIL PRESSURE SWITCH AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect oil pressure switch harness connector F111.
3. Inspect the engine harness and oil pressure switch 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.

CHECK OIL PRESSURE SWITCH RESISTANCE

Turn ignition switch OFF.
Disconnect the oil pressure switch harness connector F111.

Measure the resistance between the oil pressure switch terminal 1 and ground.

Oil pressure switch	Ground	Resistance
Terminal	Ground	Resistance
1	-	< 10 Ω

Is the inspection result normal?

YES

GO TO 4 .

Replace oil pressure switch. Refer to Removal and Installation .

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 5 .

NO

Repair or replace error-detected parts.

CHECK FOR AN OPEN CIRCUIT IN THE ENGINE HARNESS

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Disconnect the oil pressure switch harness connector F111.

Measure the resistance between the ECM harness connector F101 terminal 143 and the oil pressure switch harness connector F111 terminal 1.

ECM		Oil pressure switch		Resistance
Connector	Terminal	Connector	Terminal	Resistance
F101	143	F111	1	< 10 Ω

Is the inspection result normal?

YES

GO TO 6 .

Repair or replace the engine harness for an open.

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

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Disconnect the refrigerant pressure sensor harness connector F111.

Measure the resistance between the ECM harness connector F101 terminal 143 and all other terminals in the ECM harness connector F101.

ECM		ECM		Resistance
Connector	Terminal	Connector	Terminal	Resistance
F101	143	F101	All	> 100k Ω

Is the inspection result normal?

YES

GO TO 7 .

Repair or replace the engine harness for a short.

CHECK FOR 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 P0521-00 being past on the CONSULT screen.
Is DTC P0521-00 detected as past?

YES

The removal and installation of the connector corrected the issue.

NO

Repair or replace harness for an open.