What P052E means
The valve that controls crankcase ventilation (PCV) isn't working right. You might hear a whistle or hiss from the engine, notice a rough idle or see oil use go up. On many engines the PCV valve is built into the valve cover.
How the engine computer detects it
P052E is a function fault of the crankcase ventilation pressure regulating valve. Audi's 3.0 TFSI has a diaphragm valve whose torn diaphragm or elbow causes false air and whistling; Mercedes' M270/M274 have a switched part-load ventilation valve that blocks with oil carbon and lets oil into the intake – blue smoke, rough running, lack of power; Mercedes extended the emission warranty on the intake module. GM Europe's 2.0 diesel in the Saab 9-5 uses P052E differently, for PCV heater performance – which J2012 lists as P053D.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- Whistling or hissing in the engine bay
- Rough idle, blue smoke or oil consumption, lack of power
Common causes
- Diaphragm of the regulating valve torn or fatigued Most likely
- Part-load ventilation valve blocked (oil carbon, sludge) Most likely
- Elbow or hose at the valve cracked, clamp leaking Possible
- Engine module software Possible
How to diagnose P052E
- With the engine idling, listen for a whistle or hiss near the valve cover or oil cap.
- Try removing the oil filler cap at idle. If it's very hard to pull off or the idle changes a lot, the PCV system is faulty.
- Inspect PCV hoses for cracks and loose connections.
- Replace the PCV valve. If it's integrated into the valve cover, the whole cover is replaced.
Vehicles that report P052E most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Mercedes-Benz C300 | 2015–2016 | 74 | — | |
| Mercedes-Benz C 300 | 2017–2018 | 48 | — | |
| Mercedes-Benz GLC300 | 2016–2017 | 20 | — | |
| Mercedes-Benz GLC 300 | 2018–2019 | 17 | — | |
| Mercedes-Benz GLA 250 | 2015–2018 | 14 | — | |
| Mercedes-Benz CLA250 | 2014–2017 | 13 | — | |
| Mercedes-Benz Metris | 2016–2019 | 13 | — | |
| Mercedes-Benz E300 | 2017 | 4 | — | |
| Mercedes-Benz E 300 | 2018–2019 | 3 | — |
Counts of owner complaints to the NHTSA that mention P052E (216 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 5
- Vehicle speed, idle control and auxiliary inputs
- 2E
- Specific fault
Questions drivers ask
Can I drive with code P052E?
Yes, for a short time. Keep an eye on the oil level, because a failed PCV valve can make the engine burn or leak oil.
Will my car pass an emissions inspection with P052E?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Will P052E clear by itself?
The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.
Often reported together
Codes that owners mention in the same NHTSA complaints as P052E. They can point to a shared cause, so it's worth checking them together.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.