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 FOR CURRENT DTC
1. Turn ignition switch ON.
2. Connect CONSULT and check for other existing "ENGINE" diagnostic trouble codes.
3. Check for DTC P2048 current on the CONSULT screen.
Is applicable DTC current?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT DEF SUPPLY PUMP ASSEMBLY AND ELECTRICAL CONNECTIONS
1. Turn ignition switch OFF.
2. Disconnect the DEF dosing valve.
3. Inspect connector and 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 THE DEF DOSING VALVE
Check the DEF dosing valve. Refer to Component Inspection .

Is the inspection result normal?

YES

GO TO 4 .

NO

Replace the DEF dosing valve. Refer to Exploded View .
CHECK DEF DOSING VALVE FOR A SHORT TO GROUND
Measure the resistance between the aftertreatment DEF dosing valve SIGNAL (pin 1) and the metal case of the aftertreatment DEF dosing valve.

Is the resistance above 100 Kohms?

YES

GO TO 5 .

NO

Replace the DEF dosing valve. Refer to Exploded View .
INSPECT DEF SUPPLY PUMP ASSEMBLY AND ELECTRICAL CONNECTIONS
1. Disconnect the ECM.
2. Inspect connector and 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 6 .

NO

Repair or replace error-detected parts.

CHECK DEF DOSING VALVE CIRCUITS FOR OPEN

Check the signal and ground circuits for continuity between the ECM and the DEF dosing valve.

ECM		DEF dosing valve		Continuity
Connector	Terminal	Connector	Terminal
E93	73	C36	2	Yes
	74		1

Is the inspection result normal?

YES

GO TO 7 .

Repair open signal circuit in harness or connectors.

CHECK DEF DOSING VALVE CIRCUITS FOR SHORT

Check the continuity between DEF dosing valve circuits and ground at ECM harness connector.

ECM		Ground	Continuity
Connector	Terminal
E93	73	-	No
	74

Is the inspection result normal?

YES

GO TO 8 .

Repair short circuit in harness connector.

CHECK DEF DOSING VALVE CIRCUIT CONNECTOR FOR SHORT

Check the continuity between DEF dosing valve power circuit and all other circuits at ECM harness connector.

ECM			Continuity
Connector	Terminal	Terminal	Continuity
E93	74	All others	No

Is the inspection result normal?

YES

GO TO 9 .

Repair short circuit in harness connector.

CHECK FOR CURRENT DTC
1. Connect all harness connectors.
2. Start the engine and let it idle for 1 minute.
3. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
Is P2048 DTC current?

YES

Replace ECM. Refer to Removal and Installation .

NO

The removal and installation of the connector corrected the issue.