P051D Crankcase Pressure Sensor Circuit High Trouble Code

P051D Crankcase Pressure Sensor Circuit High

OBD-II Trouble Code Technical Description

Crankcase Pressure Sensor Circuit High

What does that mean?

This is a generic powertrain diagnostic trouble code (DTC) and typically applies to OBD-II vehicles. Vehicle makes may include but aren't limited to Ford, Dodge, Ram, Jeep, Fiat, Nissan, etc.

Among the countless sensors the ECM (Engine Control Module) has to monitor and adjust in order to keep your engine in running order, the crankcase pressure sensor is responsible for providing the ECM with crankcase pressure values in order to maintain a healthy atmosphere in there.

 

As you can imagine, there are an abundance of fumes within the engine internally, especially while its running so it is very important for the ECM to have an accurate crankcase pressure value. It needs this to not only ensure the pressure does not get too high and possibly cause damage to seals and gaskets, but also it requires this value in order to recycle these burnable fumes back into the engine via the PCV (Positive Crankcase Ventilation) system.

Any unused burnable crankcase fumes get routed into the intake for the engine to burn. In turn, collectively improving emissions and your fuel economy. That said, it definitely has a valuable purpose to the engine and ECM so make sure to address any issues accordingly here, as mentioned, with this fault, you may be susceptible to gasket failure, o-ring leaks, shaft seal leaks, etc. As the sensor's name implies, most times, it is mounted on the crankcase.

Code P051D Crankcase Pressure Sensor Circuit High and related codes get activated by the ECM (Engine Control Module) when it monitor one or multiple electrical values operate outside the desire range within the crankcase pressure sensor circuit.

When your instrument cluster is illuminated with P051D Crankcase Pressure Sensor Circuit High code, the ECM (Engine Control Module) has a high voltage condition within the crankcase pressure sensor circuit.

An example of a crankcase pressure sensor (this one for a Cummins engine):

What is the severity of this DTC?

I would say, in the grand scheme of things, this fault would be considered moderate-low. Basically, if it fails, you don't run the risk of immediate drastic further damage. I say this to stress the point that, it needs to be addressed sooner rather than later. Earlier, I mentioned some of the possible issues if left neglected so keep these in mind.

What are some of the symptoms of the code?

Symptoms of a P051D diagnostic code may include:

Reduced fuel economy Leaking gaskets Fuel smells CEL (Check Engine Light) illuminated Engine performing abnormally Sludge in oil Engine smoking black soot High/Low internal crankcase pressures

What are some of the common causes of the code?

Causes for this P051D engine code may include:

Crankcase pressure sensor defective Internal electrical issue within the sensor ECM issue PCV (Positive Crankcase Ventilation) valve defective PCV issue (broken runners/tubes, disconnected, chafed lines, etc.) Clogged PCV system Sludgy oil (moisture present) Water intrusion Engine over-filled with oil

What are some P051D diagnostic and troubleshooting steps?

The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB) for known issues with the specific vehicle.

For example, we are aware of a known issue with some Ford EcoBoost vehicles, and some Dodge/Ram vehicles that have TSBs out that apply to this DTC and/or related codes.

Advanced diagnostic steps become very vehicle specific and may require the appropriate advanced equipment and knowledge to perform accurately. We include basic steps below but refer to a vehicle year/make/model/powertrain specific repair guide for specific steps for your vehicle.

Basic

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