MERCEDES-BENZ, MERCEDES-MAYBACH · 2026-03-12
Complaint Yellow instrument cluster message: "Cooling system fault, operating energy input reduced, service required" Cause Fault code "B3A0077 - The regulation valve in the refrigerant circuit for the battery cooling gets stuck open. The ordered position cannot be achieved" stored. Faulty expansion valve component part Y140/1 Remedy Check the part number of Y140/1. If the vehicle has A 297 830 79 03 or older, replace Y140/1 with A 297 830 89 03 or newer. Do not replace Y140/1 if the installed component has part number A 297 830 8903 and a production date after February 1, 2025! Please create TIPS case, attach the current quick test and attach picture of the evaporator assembly component part label and a picture of the production date of the EXV Y140/1 (see exampled attached).