Technical Description of OBD-II Trouble Code
The circuit for the crankcase pressure sensor is experiencing intermittent or erratic behavior.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles, including Ford, Dodge, Ram, Jeep, Fiat, Nissan, and others.
The ECM (Engine Control Module) monitors and adjusts numerous sensors to ensure the engine runs smoothly. The crankcase pressure sensor is responsible for providing the ECM with accurate crankcase pressure values. This is important for maintaining a healthy atmosphere in the engine and recycling burnable fumes back into the engine via the PCV system.
If the crankcase pressure sensor circuit is not functioning properly, it can lead to gasket failure, o-ring leaks, shaft seal leaks, and other issues. The sensor is typically mounted on the crankcase.
Code P051E Crankcase Pressure Sensor Circuit Intermittent/Erratic is activated when the ECM detects electrical values outside the desired range within the crankcase pressure sensor circuit.
When your instrument cluster displays the P051E code, it means the ECM has detected an intermittent or erratic fault in the crankcase pressure sensor circuit.
Here is an example of a crankcase pressure sensor for a Cummins engine:
What is the severity of this DTC?
In the grand scheme of things, this fault is considered moderate-low. While immediate drastic damage is unlikely, it is important to address the issue promptly to avoid potential problems such as gasket failure and leaks.
What are some of the symptoms of the code?
Symptoms of a P051E diagnostic code may include:
What are some of the common causes of the code?
Causes for this P051E engine code may include:
What are some P051E diagnostic and troubleshooting steps?
The first step in troubleshooting any malfunction is to research the Technical Service Bulletins (TSB) for known issues with your specific vehicle.
For example, there are known issues with some Ford EcoBoost vehicles and some Dodge/Ram vehicles that have TSBs related to this DTC and/or related codes.
Advanced diagnostic steps will vary depending on the vehicle and may require specialized equipment and knowledge. The following are basic steps, but refer to a vehicle-specific repair guide for detailed instructions.
Basic Step #1
Inspect the oil cap on the top of the engine for signs of sludge build-up. Sludge can be caused by infrequent oil changes or following longer than recommended intervals. Check for any PCV issues that may cause moisture to enter the system and contribute to sludge. Ensure the oil is clean and at the appropriate level.
NOTE: Avoid overfilling the engine with oil. If overfilling occurs, do not start the engine and drain the oil to an acceptable level.
Basic Step #2
Test the sensor by following the manufacturer’s specified values in the service manual. Use a multimeter to test different values between pins and compare the findings to the specifications for your make and model. If the values are outside of the specified range, replace the crankcase pressure sensor.
Basic Step #3
Inspect the sensor and circuits visually, considering that crankcase pressure sensors are typically mounted directly to the engine block. Check for any cracked or hardened wires and moisture in the harness.
NOTE: Ensure the connector is firmly connected and free of oil residue.
