P052E on Mercedes-Benz
Positive Crankcase Ventilation Regulator Valve Performance
P052E on Mercedes-Benz vehicles indicates positive crankcase ventilation regulator valve performance. Au7o has documented this code across 3 Mercedes-Benz models — most commonly on G-Class, GLC, SLC. P052E indicates a performance problem with the positive crankcase ventilation (PCV) regulator valve, the valve that meters blow-by gases from the engine crankcase back into the intake to be burned. The computer monitors crankcase pressure or related readings, and when the PCV regulator isn't controlling flow within the expected range, it sets this code. Symptoms can include rough idle, oil leaks from seals due to pressure imbalance, whistling/sucking noises, or increased oil consumption. It points to the PCV valve or ventilation system rather than the fuel or ignition system. Typical repair costs on Mercedes-Benz range from $300 to $18,000, depending on the specific model and root cause.
Common Causes of P052E
- •Stuck, clogged, or failed PCV regulator valve
- •Cracked or disconnected PCV hose/line
- •Vacuum leak in the crankcase ventilation system
- •Clogged PCV passages from sludge or carbon
- •Faulty crankcase pressure sensor
- •Damaged valve cover with integrated PCV (where applicable)
- •Wiring or connector fault on electrically controlled PCV valves
P052E on Mercedes-Benz by Model
Mercedes-Benz G-Class(1 issue)
- M177 4.0L Twin-Turbo V8 Excessive Oil Consumption and Cylinder Scoring2019-2025
The 4.0L biturbo M177 V8 in the W463A G 550 and AMG G 63 is documented for above-normal engine oil consumption (often 1 quart per ~1,000-2,000 miles in worse cases), with the most severe outcome being cylinder bore/liner scoring and piston ring wear at higher mileage. The high-output, hot-running twin-turbo design stresses piston rings and the iron-coated aluminum bores; carbon buildup and ring coking aggravate consumption. If left unaddressed, low oil level can lead to bearing/piston damage. Owners report repeated low-oil warnings between services and, in advanced cases, misfires and blue exhaust smoke.
Mercedes-Benz GLC(1 issue)
- Crankcase Vent (PCV) Valve Failure with Engine Harness Oil Contamination2016-2019
The integrated PCV / crankcase breather valve in the intake manifold (M274 2.0L turbo) commonly fails or its diaphragm tears, causing unmetered vacuum leaks. Oil mist can then migrate up the engine wiring harness via capillary action, contaminating connectors. Reported predominantly on 2016-2019 GLC 300 models. When ignored, lean running and loss of crankcase regulation risk further engine damage; in the worst cases the oil-soaked engine harness also requires replacement.
Mercedes-Benz SLC(1 issue)
- Crankcase Ventilation / PCV Valve Failure2017-2020
Turbocharged 2.0L M274 engines used in the SLC 300 are known for crankcase ventilation diaphragm and PCV-related failures. When the valve assembly fails, it can create excessive vacuum or pressure in the crankcase, leading to rough idle, oil seepage, whistling noises, and lean-mixture faults.
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View P052E across all makes →Frequently Asked Questions
What does P052E mean on Mercedes-Benz?▼
P052E stands for "Positive Crankcase Ventilation Regulator Valve Performance." P052E indicates a performance problem with the positive crankcase ventilation (PCV) regulator valve, the valve that meters blow-by gases from the engine crankcase back into the intake to be burned. The computer monitors crankcase pressure or related readings, and when the PCV regulator isn't controlling flow within the expected range, it sets this code. Symptoms can include rough idle, oil leaks from seals due to pressure imbalance, whistling/sucking noises, or increased oil consumption. It points to the PCV valve or ventilation system rather than the fuel or ignition system. On Mercedes-Benz specifically, this code is documented across 3 models.
What causes P052E on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Stuck, clogged, or failed PCV regulator valve, Cracked or disconnected PCV hose/line, Vacuum leak in the crankcase ventilation system, Clogged PCV passages from sludge or carbon, Faulty crankcase pressure sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P052E on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $300 to $18,000, depending on the specific model and root cause.
Which Mercedes-Benz models have P052E documented?▼
Au7o has documented P052E on 3 Mercedes-Benz models: G-Class, GLC, SLC.