Mercedes-Benz bulletin LI01.20-P-076894
What it saysComplaint Check engine light illuminated Fault code stored in N3/10 control unit- P052E71 – Positive Crankcase Ventilation Regulator Valve Performance: The valve for crankcase ventilation has a malfunction Cause… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated May 15, 2025, received Oct 2, 2023, about the engine — 6 documents under this number. It names 27 model years (2016–2025). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationComplaint Check engine light illuminated Fault code stored in N3/10 control unit- P052E71 – Positive Crankcase Ventilation Regulator Valve Performance: The valve for crankcase ventilation has a malfunction Cause The partial-load ventilation valve (a part of the intake line assembly) may not work as intended. Remedy **Important** Replacement of the engine wiring harness or control unit is not needed if oil is found at the electrical connection of the crankcase ventilation valve or control unit. Replacement is only allowed if other symptoms or faults are present. Perform either remedy A or remedy B depending on the model Remedy A: SLK/SLC300, C350e hybrid, and GLC350e hybrid Perform guided test for fault code P052E71. Replace intake line assembly if necessary per results of the guided test. Software is not planned for models SLK/SLC300, C350e, and GLC350e. Remedy B: All other vehicles- (Replacement of intake line assembly is not required.) 1- Perform software update for N3/10 Engine control unit. 2- Remove upper engine cover. 3- Unclip ME-SFI control unit (N3/10) with bracket and place to one side with connected lines (see AR07.08-P-7013MRD). 4- Release and disconnect electrical connector (4) of partial-load operation crankcase ventilation valve (Y58/2). 5- Fit cap A094 545 50 03 on electrical connector (4) of engine wiring harness partial load operation crankcase ventilation valve (Y58/2) and ensure correct seating on plug of electrical connector (4). 6- Strap down electrical line (4) of partial load operation crankcase ventilation system valve (Y58/2) at wiring harness. Ensure that electrical line (4) is routed free of tension. 7- Clip in ME-SFI[ ME] control unit (N3/10) with bracket, ensure control unit is correctly seated at attachment points. New software part numbers: 2015-2017 C300 w/722.9 transmission- 2749021202 2749031506 2016-2018 C300 and GLC300 w/725 transmission- 2749021802 2749031806 2019 GLC300- 2749020802 2749031306 2017-2018 E300- 2749021902 2749031906 2019 E300- 2749020702 2749031206 This LI is in relation to NCU dated 8/31/2023 "Emission Extended Warranty – Intake Line Assembly".
Trouble codes it names: C350E
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI01.20-P-076894 | Service bulletin | May 15, 2025 | 11018530 | PDF, 459 KB |
| LI01.20-P-076894 | Service bulletin | Apr 15, 2025 | 11017224 | PDF, 460 KB |
| LI01.20-P-076894 | Service bulletin | Jan 17, 2025 | 11013091 | PDF, 458 KB |
| LI01.20-P-076894 | Service bulletin | May 14, 2024 | 11000623 | PDF, 41 KB |
| LI01.20-P-076894 | Service bulletin | Apr 15, 2024 | 10253722 | PDF, 36 KB |
| LI01.20-P-076894 | Service bulletin | Sep 12, 2023 | 10243308 | PDF, 41 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A094 545 50 03 | — | — |
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 010000 | Install cap on electrical connector | 0.4 hrs |
Read by machine from the document NHTSA serves (4 pages), read Sep 30, 2026. A part number is shown only where it matches Mercedes-Benz’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
Find the crankcase (pcv) for the 2020 C-Class →Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 27 model years this bulletin names have filed 1,913 complaints with NHTSA since 2015. 539 of them name Engine — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2016 Mercedes-Benz GLC-Class, the 13 owners who gave an odometer reading for Engine reported it at a median of 27,852 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
The contact owns a 2016 mercedes-benz Glc 300. The contact found NHTSA campaign number: 17v114000 (engine, transmission) pertaining to her vehicle. The part to do the repair was unavailable. The contact stated that the manufacturer exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue.
2016 Mercedes-Benz GLC-Class · Engine · filed with NHTSA Mar 6, 2017
The check engine light is on in my 2019 SLC (only 42K miles) and the car is emitting a lot of smoke from the exhaust pipe and it is hesitating while driving it. I almost got rear ended. I took it to the dealership and the fault code comes back as: P052E71 - The valve crankcase ventilation has a malfunction. The actuator is blocked.
2019 Mercedes-Benz SLC-Class · Engine · filed with NHTSA Apr 1, 2025
I brought my car in for routine service and was told I needed a rear main seal. I had the car inspected when I purchased it appx 13k miles ago because I saw online there was a lot of people having this issue with their vehicles. It’s a known manufacturer defect. At that time there was no issue. Now at 40k miles it began to leak.
2019 Mercedes-Benz E-Class · Engine · filed with NHTSA Jan 4, 2026
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group53 other manufacturer communications filed against these Mercedes-Benz models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI01.20-P-080884 | Service bulletin | Aug 12, 2026 | Complaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Reme… |
| LI07.10-P-080384 | Service bulletin | Aug 7, 2026 | Complaint Customer reports Check Engine Light with possible loss of power concern. The Following DTC's are present • P210185 - The throttle… |
| NCU - 2026010004 | Service campaign | Jul 27, 2026 | • Always use the latest XENTRY Diagnosis software release with all available add-ons. • Make sure to follow the operation steps exactly as d… |
| LI20.10-P-072886 | Service bulletin | Jul 24, 2026 | Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME… |
| Emissions - 2024100016 | Emissions | Jul 24, 2026 | Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class… |
| Emissions - 2026020006 | Emissions | Apr 24, 2026 | Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles equipped with an 8-cylinder en… |
| LI01.30-P-072328 | Service bulletin | Mar 27, 2026 | Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to m… |
| CL - EW M157 | Other | Mar 27, 2026 | Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfacti… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mercedes-Benz, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mercedes-Benz LI01.20-P-076894 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the LI01.20-P-076894 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does LI01.20-P-076894 cover?
The manufacturer filed it against 27 model years: 2020 Mercedes-Benz C-Class, 2019 Mercedes-Benz C-Class, 2018 Mercedes-Benz C-Class, 2017 Mercedes-Benz C-Class, 2016 Mercedes-Benz C-Class, 2025 Mercedes-Benz E-Class and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.