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February 6, 2025 Service bulletin

Complaint Red cooling system malfunction warning due to overheat

Mercedes-Benz technical service bulletin LI20.10-P-078510 for 2022-2024 Mercedes-Benz C300, 2023-2024 Mercedes-Benz GLE 350 and 2023 Mercedes-Benz GLE 450 and others.

Bulletin number
LI20.10-P-078510
Component
Engine
Summary
Complaint Red cooling system malfunction warning due to overheat. Low engine performance. Check engine light on. Fault codes may be stored: P21814B The cooling system has a malfunction. There is a fault due to overtemperature. P2B8500 The rpm of the coolant pump is too low. Cause Various Remedy Check for loose plug at electrical connectors of high temp coolant pump (M43/10 or M75/11) by gently pulling on connector housings. Create a TIPS case and submit to powertrain team inbox if a loose plug is found at the coolant pump. Include: -Initial quick test -Details on any damage found to engine or cooling system. Include photos if applicable. -Any other relevant details.

Owners of these vehicles have filed 17 complaints in the engine category.

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