Code Definition

P051D — Crankcase Pressure Sensor Signal High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P051D

P051D is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P051D is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P051D is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

This fault code is set when the Engine Control Module (ECM) detects a higher than expected signal from the crankcase pressure sensor. The sensor monitors the pressure inside the engine's crankcase, and the ECM uses this information for optimal engine operation and emission control. A high signal reading indicates that the pressure within the crankcase is abnormally high, which could be due to a sensor fault or actual pressure conditions within the crankcase.

Quick Facts