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 P0490-00 being current on the CONSULT screen.
Is DTC P0490-00 detected as current?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT EGR VALVE AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect EGR valve harness connector F144.
3. Inspect the engine harness and EGR valve 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 FOR AN OPEN CIRCUIT IN THE EGR VALVE MOTOR CIRCUIT

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Connect the EGR valve harness connector F144.

Measure the resistance between the ECM harness connector F101 terminals 134 and 135.

ECM			Resistance
Connector	Terminal	Terminal	Resistance
F101	134	135	< 15 Ω

Is resistance less than 15 ohms?

YES

GO TO 6 .

GO TO 4 .

CHECK FOR AN OPEN CIRCUIT IN THE EGR VALVE MOTOR

Turn ignition switch OFF.
Disconnect the EGR valve harness connector F144.

Measure the resistance between the EGR connector F144 terminals 1 and 5.

EGR valve			Resistance
Connector	Terminal	Terminal	Resistance
F144	1	5	< 15 Ω

Is resistance less than 15 ohms?

YES

GO TO 5 .

Replace EGR valve assembly. Refer to Removal and Installation .

CHECK FOR AN OPEN CIRCUIT IN THE ENGINE HARNESS

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Disconnect the EGR valve harness connector F144.

Measure the resistance between the ECM harness connector F101 and EGR harness connector F144.

ECM		EGR valve		Resistance
Connector	Terminal	Connector	Terminal
F101	134	F144	1	< 10 Ω
	135		5

Is resistance less than 10 ohms?

YES

GO TO 6.

Repair or replace the engine harness for an open.

INSPECT ECM AND HARNESS CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector F101.
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 7 .

NO

Repair or replace error-detected parts.

CHECK FOR A SHORT CIRCUIT TO VOLTAGE

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Disconnect the EGR valve harness connector F144.

Measure the voltage between the ECM harness connector F101 terminals 134, 135 and ground.

ECM		Ground	Voltage (V) (Approx.)
Connector	Terminal
F101	134	(-)	< 1.5
	135

Is the inspection result normal?

YES

GO TO 8 .

Repair or replace the engine harness for a short.

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

Turn ignition switch OFF.
Disconnect the ECM harness connector F101.
Disconnect the EGR valve harness connector F144.

Measure the resistance between the ECM harness connector F144 terminals 134, 135 and all other terminals in the ECM harness connector F101.

ECM		ECM		Resistance
Connector	Terminal	Connector	Terminal
F101	134	F101	All	> 100k Ω
	135

Is resistance greater than 100k ohms?

YES

GO TO 9 .

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 P0490-00 being past on the CONSULT screen.
Is DTC P0490-00 detected as past?

YES

The removal and installation of the connector corrected the issue.

NO

Replace ECM. Refer to Removal and Installation .