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Service bulletin LI20.10-P-074508

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11024631
Published by NHTSA2025-10-30
Manufacturer's numberLI20.10-P-074508
Manufacturer's date2025-10-28
NHTSA componentENGINE

NHTSA's summary

Complaint Check engine lamp illuminated. Fault code stored P012800-The coolant temperature is below the coolant thermostat specified temperature. Cause Various possible causes Remedy 1- Update HVAC with latest software 2- Perform guided test for fault P012800 and performed repairs per XENTRY diagnosis. - If thermostat requires replacement flush cooling circuit in both directions with 150L of water. MY 2020 GLC350e 253.953 only 3- Update the software of engine control unit N3/10. New version A2749022102 A2749032506. Note- If the guided test passes no repair should be performed. SW update for remaining hybrid models is in development for ME control unit to resolve this fault.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Trouble codes named

P0128

Vehicles listed
MERCEDES-BENZ C 350 E2018
MERCEDES-BENZ C350E2016 to 2017
MERCEDES-BENZ GLC 350 E2018
MERCEDES-BENZ GLC 350 E2020
MERCEDES-BENZ GLC350E2019

Listing a model year does not mean every vehicle of it is concerned: the document says which.