Service bulletin LI01.20-P-076894

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NHTSA's summary

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 **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".

The document

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Components

Engine

Trouble codes named

P052E

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