2014 Mercedes-Benz CLA250: Wiring Harness Repair
April 30, 2014
As it turned out, the cause of the excitement was a physical problem. A wiring harness is routed between the battery and air filter housing. In our case, tight clearances caused it to rub against the edge of the air filter box until the wiring was compromised. It was repaired per an open TSB and back in our hands the next morning.
Mercedes forums suggest that we aren't alone with this wear issue. The variance between owners seems to lie in which wires, and consequently which systems, are affected.
Mike Schmidt, Vehicle Testing Manager @ 7,850 miles