M274 Check engine light, P052E71 Crankcase ventilation valve
Topic number

LI01.20-P-076894

Version

5

Function group

01.20 - Crankcase ventilation, cylinder head cover

Date

7/8/24

Validity

Passenger car with engine M274

Reason for change

Updated remedy

Complaint
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
Model year 2018 C300 | Model year 2016-2018 GLC300 and E300 | ALL model year SLK/SLC300 and hybrid variants
Performed guided test for fault code P052E71. Replace intake line assembly if necessary per results of the guided
test. This LI will be updated once the software solution is available for model year 2018 C300 and 2016-2018 GLC300
and E300 vehicles.
Model year 2015-2017 C300 | Model year 2019 GLC300 and E300
Perform software update for N3/10 Engine control unit. Replacement of intake line assembly is not required.
New software part numbers:
2015-2017 C300- 2749021202 2749031506
2019 E300- 2749020702 2749031206
2019 GLC300- 2749020802 2749031306

This LI is in relation to NCU dated 8/31/2023 "Emission Extended Warranty – Intake Line Assembly".

WIS-References
Document number
23.07.2024 17:57
© Copyright Mercedes-Benz AG

Title

Note
CCUSHWA

Page 1 / 2

AR01.20-P-9692MRU

Remove/install oil separator on crankcase

Disclaimer
NOTE: The information contained in this document is intended for use by trained, professional technicians with the
knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz
approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and
provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect
is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a
symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes
resulting in the same or similar symptoms or conditions described in this document, and trained professional service
technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained
in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

Symptoms
Power generation > Exhaust system > Function > Fumes/blue smoke
Power generation > Engine management > Engine running > Runs rough/shakes
Power generation > Engine management > Indicator lamp > Engine diagnosis > lit
Power generation > Engine management > Engine performance > No/poor output

Parts
Part number

ES1 ES2 Designation

A274090560080

Quantity Note

Intake line assembly

1

EPC

inclusive of oil separator, partial load
ventilation valve and full-load ventilation valve

X

Control unit/fault code
Control unit

Fault text

N3/10 - Motor electronics 'MED40' for combustion engine P052E71 - The valve for crankcase ventilation has a mal'M274' (ME) (MED40)
function. The actuator is blocked.

Operation numbers/damage codes
Op. no.

Operation text

Time

Solenoid valve, crankcase ventilation
system

23.07.2024 17:57
© Copyright Mercedes-Benz AG

CCUSHWA

Damage
code

Note

0101D

Damage code

Page 2 / 2