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. Are any of the following displayed as current on the CONSULT screen.
  - P051C-00
  - P051D-00
Is applicable DTC detected?

YES

Refer to DTC Index .

NO

GO TO 2 .
CHECK OIL FILL CAP
Check the oil fill cap for proper installation.

Is the inspection result normal?

YES

GO TO 3 .

NO

Install oil fill cap.
INSPECT CRANKCASE PRESSURE SENSOR AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor harness connector F151.
3. Inspect the harness connector and crankcase pressure sensor 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 THE CIRCUIT RESPONSE
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor harness connector F151.
3. Turn ignition switch ON and wait 30 seconds.
4. Connect CONSULT and check for current ENGINE diagnostic trouble codes.
Did P051C-00 DTC become current?

YES

GO TO 5 .

NO

GO TO 6 .
CHECK THE CIRCUIT RESPONSE
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor harness connector F151.
3. Connect a jumper wire between crankcase harness connector F151 terminals 1 and 3.
4. Turn ignition switch ON and wait 30 seconds.
5. Connect CONSULT and check for current ENGINE diagnostic trouble codes.
Did P051D-00 DTC become current?

YES

Replace crankcase pressure sensor. Refer to Removal and Installation .

NO

GO TO 6 .
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 THE CIRCUIT RESPONSE
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector F101.
3. Turn ignition switch ON and wait 30 seconds.
4. Connect CONSULT and check for current ENGINE diagnostic trouble codes.
Is DTC P051C-00 current?

YES

GO TO 8 .

NO

Replace ECM. Refer to Removal and Installation .
CHECK THE CIRCUIT RESPONSE
1. Turn ignition switch OFF.
2. Connect a jumper wire between ECM harness connector F101 terminals 106 and 111.
3. Turn ignition switch ON and wait 30 seconds.
4. Connect CONSULT and check for current ENGINE diagnostic trouble codes.
Is DTC P051D-00 current?

YES

Repair or replace harness for an open or short circuit.

NO

Replace ECM. Refer to Removal and Installation .