Cooling System Malfunction Error Message




It was cold at the time, 16 degrees F, but coolant level was fine.
This has been reported in another forum here with lots of causes - Error message cooling system malfunction reduced drive performance - MBWorld.org Forums
Anyone with a W223 have the issue?
Last edited by Mem30306; Jan 27, 2026 at 08:54 AM.










Dealership where it was purchased said to keep an eye on it. We opted to make a pit stop in Spokane, shout out to the dealership. Their tech tore into it and discovered that one of the antifreeze reservoirs (the vehicle has two) was down by a cup. He gave me instructions for checking both reservoirs should it happen again. It never has.
JR
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Dealership where it was purchased said to keep an eye on it. We opted to make a pit stop in Spokane, shout out to the dealership. Their tech tore into it and discovered that one of the antifreeze reservoirs (the vehicle has two) was down by a cup. He gave me instructions for checking both reservoirs should it happen again. It never has.
JR
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