OBD2 Car ScannerWhat does P051C mean?
P051C stands for Crankcase Pressure Sensor Circuit Low. The engine computer has found a problem with vehicle speed signals, idle control or another sensor input.
Powertrain codes cover the engine, transmission and emissions. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Faulty vehicle speed sensor
- Dirty throttle body or idle air control valve
- Faulty switch or sensor
- Damaged wiring or connector
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does P051C mean?
P051C means “Crankcase Pressure Sensor Circuit Low”. It belongs to the speed, idle control and inputs group: The engine computer has found a problem with vehicle speed signals, idle control or another sensor input.
Is it safe to drive with P051C?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear P051C?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- P0518Idle Air Control Circuit Intermittent
- P0519Idle Air Control System Performance
- P051ACrankcase Pressure Sensor Circuit
- P051BCrankcase Pressure Sensor Circuit Range/Performance
- P051DCrankcase Pressure Sensor Circuit High
- P051ECrankcase Pressure Sensor Circuit Intermittent/Erratic
- P051FPositive Crankcase Ventilation Filter Restriction
- P0520Engine Oil Pressure Sensor/Switch Circuit Malfunction
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.