P052E: Positive Crankcase Ventilation Regulator Valve Performance
Severity: medium
What it means: The engine computer can't get the crankcase pressure it wants using the electronically controlled crankcase ventilation (PCV) regulator valve, so it sets this code.
Safe to drive? Usually drivable to a shop, but a crankcase ventilation fault can cause oil leaks, oil use or a rough idle over time. Get it checked soon.
Common symptoms
- Check-engine light, sometimes coming and going
- Oil leaks or higher oil use
- Rough idle or whistling from the engine
Likely causes, ranked
- Blocked or failed crankcase ventilation (PCV) regulator valve or actuatorShop
- Cracked, clogged or disconnected crankcase ventilation hosesDIY
- Faulty crankcase pressure sensor or wiringShop
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Vehicle-specific notes
- 2016–2022 Mercedes-Benz GLC: A 2018 GLC 300 owner on Car Talk had a check engine light that came and went for a long time. The dealer's invoice read 'P052E71 The valve for crankcase ventilation has a malfunction. The actuator is blocked.' It was fixed under the extended warranty with a plug and a software update. Read the full answer · Source
DIY or shop?
Checking the ventilation hoses is DIY. The electronic regulator valve and sensor are usually shop work, and on some cars a software update is part of the fix.
Before you replace parts
- Read all stored codes, including any letters or numbers after P052E (like P052E71), and keep the list.
- Ask whether your warranty or extended warranty covers the crankcase ventilation valve.
- Check your VIN at nhtsa.gov/recalls for open recalls.
- Inspect the ventilation hoses for cracks or oil-soaked connections.
- Clear the code only after a repair, then confirm it stays off.
Safety / mechanic note
Verify with a mechanic. A code points to a system, not always a specific part.
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