Code Definition

P051C — Crankcase Pressure Sensor Signal Low

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

About P051C

P051C 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 P051C is stored, the module has detected a signal or supply voltage lower 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 P051C 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 logged when the Engine Control Module (ECM) detects a lower than expected signal from the crankcase pressure sensor. The crankcase pressure sensor measures the pressure within the engine's crankcase, and the ECM uses this data for engine management and emission control purposes. A low signal from this sensor could indicate a condition where the pressure in the crankcase is abnormally low, potentially due to sensor malfunction or an actual change in crankcase conditions.

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