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 P202C 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.
2. Disconnect the DEF supply pump assembly harness connector.
3. Inspect the DEF supply pump assembly harness and 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. Wait at least 90 seconds before proceeding to allow sufficient time for the aftertreatment DEF control module to completely power down.
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

Check the continuity between DEF tank heater supply circuit and all other circuits at the DEF control module connector.

DEF control module			Continuity
Connector	Terminal	Terminal	Continuity
C205	22	All others	No

Is the inspection result normal?

YES

GO TO 5 .

Repair or replace short circuit in harness.

CHECK DEF TANK HEATER RETURN CIRCUIT FOR SHORT

Check the continuity between DEF tank heater return circuit and all other circuits at the DEF control module connector.

DEF control module			Continuity
Connector	Terminal	Terminal	Continuity
C205	23	All others	No

Is the inspection result normal?

YES

GO TO 6 .

Repair or replace short circuit in harness.

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.
4. With CONSULT check for current "ENGINE" diagnostic trouble codes.
Is P202B DTC current and P202C DTC past?

YES

A short circuit 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 .