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 AN ACTIVE DTC
If DTC CONFIRMATION PROCEDURE has been previously conducted, always perform the following procedure before conducting the next test.
1. Turn ignition switch ON.
2. Connect CONSULT and check for existing "ENGINE" diagnostic trouble codes.
3. Check for DTC P202B being current on the CONSULT screen.
Is applicable DTC current?

YES

GO TO 2 .

NO

Refer to Intermittent Incident .
INSPECT DEF SUPPLY PUMP ASSEMBLY AND CONNECTOR PINS
1. Turn ignition switch OFF and wait at least 90 seconds before proceeding to allow sufficient time for the aftertreatment DEF supply pump assembly to completely power down.
2. Disconnect the DEF supply pump assembly harness connector.
3. Inspect the DEF supply pump assembly 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 DEF CONTROL MODULE HARNESS CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect the DEF control module harness connector.
3. Inspect 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 DEF TANK HEATER SUPPLY CIRCUIT FOR SHORT TO GROUND

Check the continuity between DEF tank heater supply circuit and ground.

DEF control module			Continuity
Connector	Terminal	Terminal	Continuity
C205	22	Ground	No

Is the inspection result normal?

YES

GO TO 5 .

Repair or replace short circuit in harness.

CHECK DEF TANK HEATER CIRCUITS FOR OPEN

Check the supply and return circuits for continuity between the DEF control module harness connector and DEF supply pump assembly harness connector.

DEF control module		DEF supply pump assembly		Continuity
Connector	Terminal	Connector	Terminal
C205	22	C204	1	Yes
	23		3

Is the inspection result normal?

YES

GO TO 6 .

Repair open circuit in harness or connectors.

CHECK THE CIRCUIT RESPONSE
1. Reconnect the DEF control module harness connector.
2. Connect a jumper wire between disconnected DEF supply pump assembly connector pins 1 and 3.
3. Turn ignition switch ON, start engine, and allow the engine to idle for 1 minute.
4. With CONSULT check for current "ENGINE" diagnostic trouble codes.
Is P202C DTC current and P202B DTC past?

YES

An open circuit or short circuit-to-ground has been detected in the aftertreatment DEF tank heater, which is internal to the aftertreatment DEF dosing unit. Replace the aftertreatment DEF dosing unit. Refer to Removal and Installation .

NO

Replace the DEF control module. Refer to Removal and Installation .