MERCEDES-BENZ · 2025-02-06
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.