Recently we have seen a number of Mercedes from the CLA, E Class and A Class models suffering with the battery warning message and failing to start. One of the vehicles indeed had flat or low voltage supplied by the battery but the other two had low voltage error store in the ecu but did not have a low voltage at the battery itself after performing a number of resets the fault both remained away.
The reset performed as far as we are aware can ONLY be performed using Mercedes Star / Mercedes Xentry. Luckily for us we have both Mercedes Star and Mercedes Xentry on hand to perform these tasks.
If you are based in Suffolk, Essex or Norfolk we are on hand to help.