I have run into an issue where seemingly at random, my 2010 M3 will not start when I push the button. Key is in, foot is on the brake, lights and everything come on, but the engine doesn't turn over. Later in the day, car will fire up immediately.
What might be the issue?
EDIT: I found a workaround, and have a thought to the culprit.
Workaround: with foot OFF brakes, push start button, then put foot ON brakes, push start button again to start the car.
Thoughts on reason: the brake pedal has a lot of pressure, so I can not push the brakes hard enough for it to register that it is being pressed due to back pressure from master cylinder.
Last edited by DerStig; 05-23-2018 at 07:16 PM. Reason: Accidental problem-solution discovery
Sounds like maybe the brake switch not triggering? Reasonable guess...
So The problem of having the car not start has resurfaced, but under a different set of circumstances. I have no idea why the car does not want to start.
Some ways other people have fixed this issue are:
-Starter
-car battery
-master relay and clutch switch (no entirely applicable due to dct)
-key fob (has comfort access, so might be a dying battery
-the brake light switch
I would like some input as to what other people have experienced with the push button start failing to start the car.
I just worked on a 2008 e60 with a no start ... in this case, it turned out to be a broken engine ground strap (after we replaced the starter ... sigh). Unlikely in your case, but maybe check all your battery terminals and ground points, make sure they are not loose?
Grounds are an issue in the E9xM3. I did not believe it. I checked mine this spring and they were intact so I treated them with deoxit. 6 months later I had a slower start when cold and a barely start or no start when hot. My garage was under renovation and my tools in storage so I could not put the car on the lift line I normally would do. I changed the battery. No change. I changed the alternator. No change. I changed the starter. It did spin a little faster after that but was still slow or barely starting when hot. Then I tried using jumper cables as a double ground for testing purposes. Started right up hot. Installed an old battery cable as a temporary block to chassis ground in the engine bay until my lift and garage are done. Worked fine since. Hope to redo the under car grounds in the next month.
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