P051D

P051D-CRANKCASE PRESSURE SENSOR CIRCUIT HIGH







Theory of Operation

The Crankcase Pressure Sensor is used to monitor the pressure inside the crankcase. The Engine Control Module (ECM) supplies the Crankcase Pressure Sensor a 5-Volt reference voltage. When the crankcase pressure is low, the sensor signal voltage is low. When the crankcase pressure is high, the sensor signal voltage is near the 5-Volt reference voltage. The ECM monitors the Crankcase Pressure Sensor Signal circuit voltage to calculate the pressure of the air within the crankcase. The ECM does not illuminate the MIL or ETC lamp for any of the crankcase pressure faults.

- When Monitored:
Ignition on, engine not running.

- Set Condition:
The circuit voltage to the Engine Control Module (ECM) is above a calibrated threshold for a calibrated time.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. OTHER DTCS
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.

Are there any 5-Volt Reference DTCs present?

Yes

- Repair the 5-Volt Reference DTCs before proceeding.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. P051D ACTIVE

Is DTC P051D active?

Yes

- Go To 3

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test.

3. CHECK FOR THE (K926) CRANKCASE PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO ANOTHER CIRCUIT
1. Turn the ignition off.
2. Disconnect the Crankcase Pressure Sensor harness connector.
3. Disconnect the ECM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

4. Measure the resistance between the (K926) Crankcase Pressure Sensor Signal circuit and all other circuits of the ECM C1 harness connector.

Is the resistance below 10k Ohms between the (K926) Crankcase Pressure Sensor Signal circuit and all other circuits?

Yes

- Repair the (K926) Crankcase Pressure Sensor Signal circuit for a short to the circuit that measured below 10k Ohms.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK THE (K916) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE




1. Measure the resistance of the (K916) Sensor Ground circuit between the Crankcase Pressure Sensor harness connector and the ECM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the (K916) Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. CHECK THE CRANKCASE PRESSURE SENSOR
1. Reconnect the Crankcase Pressure Sensor harness connector.
2. Reconnect the ECM C1 harness connector.
3. Turn the ignition on.
4. While monitoring the scan tool, disconnect the Crankcase Pressure Sensor harness connector.

Does the scan tool display P051C Crankcase Pressure Sensor low DTC as active or pending?

Yes

- Replace the Crankcase Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the Engine Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.