C63 refused to start this morning, unlocked the car, turned the key, all lights on but nothing from the starter motor, I tried a few times but eventually gave up, then I thought maybe battery in the key so checked the voltage 3V on each cell so no problem there, went out and tried again and it started and has been fine ever since, it's going in for a diagnostic check on Monday to see if anything has been logged but before that happens can anybody shed light as to what the problem could be?