MERCEDES-BENZ

LI20.30-P-078333

2025-03-21 · NHTSA 11016022

A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

Manufacturer summary

Original wording in English

Complaint A "Coolant level too low" warning message is shown in the instrument cluster. Fault code P25567B ('Coolant level' sensor has detected a fault, fluid level is too low.) is stored in the signal acquisition and actuation module (SAM) control unit N10. Cause The vehicle's electric drive motor transports air into the cooling system. The air transported into the cooling system leads to the formation of an air cushion in the expansion reservoir, which in turn causes the coolant level to drop below the warning threshold of the coolant's fill level sensor when driving. After opening the closing cap, the coolant level is OK again. Remedy Replace the black cap A210 501 06 15 of the large working chamber of the expansion reservoir with a red cap A297 500 51 00 and the coolant level rises by roughly 20 mm above the MAX. marking. On vehicles in which the problem cannot be rectified by this procedure, the expansion reservoir A 243 500 41 00 is replaced by the modified container A243 500 60 00. The new expansion reservoir is to have two red closing caps A 297 500 51 00 fitted to it, and the coolant level is to be set to the MAX. marking.

Repeated filings are grouped only when make, bulletin number, publication date and complete summary agree. Original record numbers are retained. Older publications remain available, and an explicit later version is shown when established. Pre-1994 vehicle associations are separated from default results; an unspecified year does not mean all model years apply.