One problem related to wiring has been reported for the 2014 Mercedes Benz CLA250. The most recently reported issues are listed below.
Traveling approximately 15mph and slowly accelerating, vehicle became completely unresponsive to throttle input, and engine remained at idle speed. Displayed showed the messages "pre-safe inoperable" and "see owner's manual. " after the engine was shut off and restarted, the car drove normally. It was taken into the dealer for inspection and repair, and was returned to me after the service adviser advised me that they could "find no codes. " the very same error occurred a few days later. This time the service adviser said that error codes were found, that there was a "conflict in the programming", that all of the hardware checked out, and that "reprogramming the module" will fix it. 36 hours later it occurred again. This time the adviser said that a Mercedes Benz service database indicated that the problem was with a wiring harness in the throttle, and that replacing that harness will fix the problem.