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 other existing "ENGINE" diagnostic trouble codes.
If DTC P21CA-00 is present, perform the confirmation procedure (trouble diagnosis) for this other DTC first.

Is applicable DTC detected?

YES

Perform diagnosis of applicable DTC. Refer to DTC Index .

NO

GO TO 2 .
CHECK FOR CURRENT DEF LEVEL SENSOR DTC
Check for DTC P203B-00 being current on the CONSULT screen.

Is applicable DTC current?

YES

GO TO 3 .

NO

Refer to Intermittent Incident .
INSPECT DEF SUPPLY PUMP ASSEMBLY AND ELECTRICAL CONNECTIONS
1. Turn ignition switch OFF.
2. Disconnect the DEF supply pump assembly connector.
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 4 .

NO

Repair or replace error-detected parts.

CHECK DEF LEVEL SENSOR POWER SUPPLY CIRCUITS

Turn ignition switch ON.

Check the voltage between DEF supply pump assembly connector sensor supply voltage and ground circuit terminals.

DEF supply pump assembly

Voltage (V)

(Approx.)

Connector

Terminal (+)

Terminal (-)

C204

Approx. 5

Is the inspection result normal?

YES

GO TO 5 .

Repair or replace the DEF control module harness for open or high resistance.

INSPECT DEF CONTROL MODULE AND ELECTRICAL CONNECTIONS
1. Disconnect the DEF control module.
2. Inspect both connectors 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 TANK LEVEL SENSOR CIRCUITS FOR OPEN

Check the signal and ground circuits for continuity between the DEF control module and the DEF supply pump assembly.

DEF control module		DEF supply pump assembly		Continuity
Connector	Terminal	Connector	Terminal
C205	20	C204	6	Yes
	26		14

Is the inspection result normal?

YES

GO TO 7 .

Repair open signal circuit in harness or connectors.

CHECK THE CIRCUIT RESPONSE
1. Reconnect the DEF control module.
2. Connect a jumper wire between DEF supply pump assembly 5 volt supply terminal 5 and signal circuit terminal 6.
3. Turn ignition switch ON and wait 30 seconds.
4. Connect CONSULT and check for current "ENGINE" diagnostic trouble codes.
Did P203C-00 DTC become current?

YES

A damaged tank level sensor has been detected. Replace the aftertreatment DEF supply pump assembly. Refer to Exploded View .

NO

Replace the DEF control module. Refer to Exploded View .