Mercedes M274 P052E71: model-specific ventilation repair branches. See the manufacturer document, vehicle conditions, exclusions and questions for a qualified shop before assuming a repair.
This is a research summary of a manufacturer communication, not a diagnosis for your car, a DIY repair procedure or confirmation of warranty or recall eligibility. No qualified technician has approved a repair for your individual vehicle here.
This historical communication is conditional. The current revision, VIN/build eligibility, measured diagnosis and any warranty or recall decision are not established here. Ask the manufacturer or a qualified shop to check the complete current document.
Read the Mercedes-Benz original: M274 crankcase-ventilation P052E71 and model-dependent remedies · Check open recalls by VIN at NHTSA Source date: 2025-01-17; research checked: 2026-11-01.
What prompted this manufacturer document
- The fault concerns crankcase-ventilation regulator performance.
- Oil at a connector alone does not justify replacing the engine harness or ECU.
Which vehicle conditions must be checked
Each row below retains its own conditions. Do not combine engines, years or models across rows to create new applications. A listed model is not proof that a particular VIN is affected.
- Mercedes-Benz M274-equipped passenger cars · year not established · M274; VIN/engine and individual branch required
- Mercedes-Benz SLK 300 / SLC 300 · year not established · M274; Special intake-line/diagnostic branch
- Mercedes-Benz C 350 e / GLC 350 e · year not established · M274 hybrid; Special intake-line/diagnostic branch
- All listed SLK/SLC 300 and C350e/GLC350e applications use the special guided-test/intake-line branch.
- The document does not plan the other software remedy for that special group.
Codes recorded in this document
A root listed only as an appearance has no separately verified meaning here. Preserve every suffix and module name; a shared root does not transfer a repair branch to another vehicle.
| Root | Raw form | Meaning in this source, if established |
|---|---|---|
| P052E | P052E71 | Crankcase-ventilation regulator performance malfunction; retain suffix 71 in this Mercedes application. |
What an owner can record safely
- Record the exact suffix 71 and the vehicle engine/hybrid identity.
What the source does not prove
- Do not unplug control wiring as a DIY emissions workaround or assume an oily connector condemns an ECU.
- A code or message alone does not establish a failed part, a safe-to-drive decision or an approved repair for this VIN.
- A service bulletin is not automatically a recall or free warranty repair. Confirm current eligibility directly.
Questions for the repair shop
- Which model branch applies, and what diagnosis supports replacing an intake line rather than updating software?
- Does a later revision or a current recall change the source's original advice?
- What measurement or inspection confirms the cause, and how will the repair be verified?
Open source-review issue
- Q2-009: The source names an engine or chassis family without a complete US make/model-year matrix. Do not extend it to another model from brand familiarity.
The uncertain field is not used here to claim a current fitment, repair or market-wide failure.
Read the original record
The linked communication may be revised after the research date. Compare its document number, exact vehicle table, diagnostic preconditions and exclusions with a qualified technician. This page paraphrases selected facts and does not reproduce the manufacturer procedure.
Sources and scope
- Mercedes-Benz — M274 crankcase-ventilation P052E71 and model-dependent remedies (LI01.20-P-076894 version 7) Document: 2025-01-17 · Research checked: 2026-11-01
Research snapshot: 2026-11-01. Source documents may have newer revisions. Verify current instructions and VIN eligibility with the manufacturer.