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. Check for sensor supply DTCs being current on the CONSULT screen.
Is applicable DTC detected?

YES

Refer to DTC Index .

NO

GO TO 2 .
CHECK DTC PRIORITY
1. Turn ignition switch ON.
2. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
3. Check for DTC P051C being past on the CONSULT screen.
Is DTC P051C-00 detected as past?

YES

Refer to Intermittent Incident .

NO

GO TO 3 .
INSPECT CRANKCASE PRESSURE SENSOR AND CONNECTOR PINS
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor harness connector F151.
3. Inspect the engine harness and 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 4 .

NO

Repair or replace error-detected parts.

CHECK THE SENSOR SUPPLY VOLTAGE AND RETURN CIRCUIT

Turn ignition switch OFF.
Disconnect the crankcase pressure sensor harness connector F151.
Turn ignition switch ON.

Measure the voltage between crankcase pressure sensor harness connector F151 terminals 1 and 2.

Crankcase pressure sensor

Voltage (V)

(Approx.)

Connector

Terminal

F151

4.75-5.25

Is inspection result normal?

YES

GO TO 5.

GO TO 7.

CHECK THE CIRCUIT RESPONSE
1. Turn ignition switch OFF.
2. Disconnect crankcase pressure sensor connector F151.
3. Connect a jumper wire between crankcase pressure sensor 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 DTC P051D-00 become current and DTC P051C-00 become past?

YES

GO TO 6.

NO

GO TO 10 .
CHECK DTCS AND VERIFY SENSOR CONDITION
1. Turn ignition switch OFF.
2. Connect the 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.
Is DTC P0051C-00 current?

YES

Replace the crankcase pressure sensor. Refer to Removal and Installation .

NO

The removal and installation of the connector corrected the issue.
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 8 .

NO

Repair or replace error-detected parts.

CHECK THE SENSOR SUPPLY VOLTAGE AND RETURN CIRCUIT

Turn ignition switch OFF.
Disconnect harness connector F101 from the ECM.
Turn ignition switch ON.

Measure the voltage between terminals 106 and 127 at the ECM connector F101.

ECM

Voltage

(Approx.)

Connector

Terminal

F101

127

106

4.75-5.25

Is the inspection result normal?

YES

GO TO 9.

Replace the ECM. Refer to Removal and Installation .

CHECK FOR PAST DTC
1. Connect all components.
2. Turn ignition switch ON.
3. Connect CONSULT and check for ENGINE diagnostic trouble codes.
4. Check for DTC P051C-00 being past on the CONSULT screen.
Is DTC P051C-00 detected as past?

YES

The removal and installation of the connector corrected the issue.

NO

Repair or replace harness for an open.
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 11 .

NO

Repair or replace error-detected parts.
CHECK THE ECM RESPONSE
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector F101.
3. Connect a jumper wire between crankcase pressure sensor harness connector F101 terminals 106 and 111.
4. Turn ignition switch ON. Wait 30 seconds.
5. With CONSULT check for current ENGINE diagnostic trouble codes.
Did P0051D-00 DTC become current and P051C-00 DTC become past?

YES

GO TO 12 .

NO

Replace the ECM. Refer to Removal and Installation .
CHECK DTC PRIORITY
1. Connect all components.
2. Turn ignition switch ON.
3. Connect CONSULT and check for "ENGINE" diagnostic trouble codes.
4. Check for DTC P051C-00 being current on the CONSULT screen.
Is DTC P051C-00 detected as current?

YES

Repair or replace harness for an open or pin-to-pin short.

NO

The removal and installation of the connector corrected the issue.