What does it mean?
NOTE: P051B is common on 2015 and newer Ford vehicles with EcoBoost engines (1.5L, 2.7L, 3.5L). Vehicles affected include Ford Escape, EcoSport, F-150, Fusion, Ranger, etc. This code may be due to the crankcase pressure sensor/tube assembly. To correct the condition, check TSBs and follow the Service Procedure steps to replace the crankcase pressure sensor/tube assembly. The Diagnostic Trouble Code (DTC) P051B is a trouble code that means Crankcase Pressure Sensor Circuit Range/Performance.
It has to do with monitoring the pressure level that is gathering up in the engine. The crankcase pressure sensor does not just monitor pressure but also the engine oil present in the crankcase. The DTC works using a pressure sensor that correctly measures and determines the pressure building level in the crankcase. This is to prevent the gaskets and other seals from getting damaged. To understand how important the Crankcase Pressure Sensor is, we will briefly explain the crankcase.
The Crankcase is the largest part of the engine. It houses the important parts of the engine like the connecting rods, pistons, and cylinders. Any damage to any part of this part of the engine could be fatal to the totality of the engine; this is why this part of the engine must be monitored properly. The Crankcase Pressure Sensor is created to ensure that the engine works under a suitable internal condition.
During normal working conditions, the engine produces a lot of gas that continuously builds up within the engine. These gases are normal during the engine’s operation but could also be dangerous if not monitored properly. Excessive gas or pressure in the engine’s crankshaft can cause the engine to have oil leaks and can cause leaks in other engine seals, including the gasket. The Crank Pressure Sensor monitors these gases in the engine’s crankshaft.
It works with the Engine Control Module (ECM), popularly considered the “brain.” The ECM performs the function of monitoring the engine’s performance and making sure that it functions perfectly. All modern vehicles come with an ECM system. All the car’s engine sensors are connected to the ECM system, ensuring that all the vehicle parts are working at optimal capacity. ECM helps regulate major engine parts, including a mixture of air and fuel and an emission system.
The Crank Pressure Sensor works with the ECM system by sending valuable data about the condition of pressure in the crankshaft to the ECM. The ECM then ensures that the gases do not reach a harmful extent. It does this by redistributing the gases into the engine for use. The ECM can achieve this with the help of a Positive Crankshaft Ventilation (PVC) system.
The P051B Code can get activated when the data from the Crank Pressure Sensor shows that the pressure built up in the crankshaft is above the normally required pressure. The sensors in the crankshaft pick up the problem. The sensors then send the data to the ECM, which triggers the Positive Ventilation (PVC) system to correct the problem. If the problem can not be regulated due to issues within the engine system or external factors, then the P051B is triggered.
The code is shown on the OBD system, telling you that there is a problem with the engine pressure level.