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 CRANKCASE PRESSURE SENSOR DTC PRIORITY
1. Turn ignition switch ON.
2. Connect CONSULT and check ENGINE diagnostic trouble codes for the following:
  - P051C-00
  - P051D-00
Is any applicable DTC detected as current or history?

YES

Perform diagnosis of applicable DTC. Refer to DTC Index .

NO

GO TO 2 .
CHECK THE OIL FILL CAP
1. Turn ignition switch OFF.
2. Check the oil fill cap for proper installation.
Oil fill cap properly installed?

YES

GO TO 3 .

NO

Install the oil fill cap properly.
CHECK THE CRANKCASE FILTER TUBE
1. Check the crankcase breather tube between the engine and the crankcase filter assembly.
2. Make sure the breather tube is properly connected and there are no kinks or other restrictions present
Crankcase breather hose connected properly and free of restrictions?

YES

GO TO 4 .

NO

Properly connect the crankcase breather hose.
INSPECT THE CRANKCASE PRESSURE SENSOR AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor harness connector.
3. Inspect the crankcase pressure sensor 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 5 .

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. 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 ON and wait 30 seconds.
2. 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 ECM RESPONSE
CAUTION:
When probing or jumping between connector pins or terminals:
- Always use extreme care or connector damage could result. Do not bend or damage connector pins and terminals. Damaged connectors, pins or terminals could result in additional issues or difficult-to-diagnose intermittent incidents.
- Do not probe or short unintended circuits or component and/or control module damage could result.
1. Turn ignition switch OFF.
2. Connect a jumper wire between ECM connector F101 pins 106 and 111.
3. Turn ignition switch ON and wait for 30 seconds.
4. With CONSULT check for current ENGINE diagnostic trouble codes.
Is P051D-00 DTC current?

YES
- High resistance or short circuit has been detected in the engine harness. Repair or replace the engine harness.
- GO TO 9 .
NO
- Replace the ECM. Refer to Removal and Installation .
- GO TO 9 .
CHECK FOR CURRENT DTC
1. Turn ignition switch OFF.
2. Disconnect the jumper wire.
3. Connect all harness connectors.
4. Turn ignition switch ON.
5. Using CONSULT, erase ENGINE diagnostic trouble codes.
6. Operate the engine within the "Conditions for clearing the DTC".
7. Connect CONSULT and check for current ENGINE diagnostic trouble codes.
Is P04DB-00 DTC current?

YES

Troubleshooting procedure need to be repeated. Go to DTC Description .

NO

The removal and installation of the connector corrected the issue.