Start/Stop Button Does Not Operate

I own a 2006 530i and my car won't start after pressing the start/stop button. This happened on May 4th and I had to have my car towed to the dealer. As of today, they have been unable to get the car started. They have tried the following in sequence from what they've described to me:

1) They replaced the ignition control unit which they had to have BMW Germany send them because this ignition control unit had be coded to my serial number. This didn't start the car so they put my original ignition control unit back in.
2) They then replaced what I was told is called a junction box. The Service Rep said this basically supplies power to the entire car. This didn't start the car either.
3) They then did a wire by wire / pin by pin check of the electrical system to determine if there is a short or something that is preventing the car from starting. They found nothing wrong with the electrical system through this process. At this point, they also have a BMW Factory Engineer working on my car.
4) Today, I was told they will now replace something called the megatron unit. The Service Rep stated this is a 2 piece unit which includes the control unit and the valve body. They have ordered this part and are waiting for it to arrive. However, this may or may not start the car.

So, I'm going on 2 weeks without BMW determining the actual cause of the problem. Of course, I'm quite frustrated and angry the problem hasn't been found given this is a new car and quite expensive as we all know. I figured I'd post this and see if any of you BMW owners can add any further insight. Thanks!

Won't start as in nothing happens at all...Or...

I think we will need a little more info before we can begin our wild speculation...

Originally Posted by sats530i

4) Today, I was told they will now replace something called the megatron unit.

Tomorrow they will replace the optimus prime unit... i know, not very helpful but couldn't help it...


Sorry to hear about the car man.. hope they can figure it out for you soon!

Basically, nothing happens. The car doesn't start at all. The strange thing is when the access key is pushed in, the radio and the "BMW" appears for about 3 seconds then everything just shuts down. Also, certain electronic components work with the access key pushed in like windows, locks, side mirrors, seats, headlights, however the sunroof/moonroof and the fan/ac haven't worked since the day the start/stop button stopped working.

Having no basis except being a Systems Engineer by trade, I'd guess it is the ignition control unit and you just got one fromt he factory that was not setup correctly or was bad to start with.

My gut also says your keys could be bad as well as the ignition control unit... (like when the ignition control unit died it sent bad data and scrambled the keys?)

Years of dealing with crappy Cisco hardware/software has given me this bitter outlook on quality control.

If this last fix doesn't do it, immediately make a claim under your state's lemon law. If you don't know how, consult an attorney. Usually it's 3 attempts to fix the same problem that substantially impedes on the performance or operation of the vehicle within the first 18,000 miles or first year. Your state, California, could be different. You have to look up your lemon law.

If you have to send out notices do so by certified and regular mail, and send to everyone involved (ie. your dealer, BMW NA, and whatever state department or office that deals with lemon law claims)

Good luck.