M3 Shut Off While Driving

Hey guys

I've tried searching all over but I haven't been able to find much about this. If you guys could help that would be great.

My brother was driving his 2009 M3 the other day and he was pushing the car going about 80 when it just shut off by itself. He managed to get the car to the side of the road but it wasn't starting again. We tried jumping it but it didn't work. While we were trying to start it and playing around with the electronics the battery was getting weaker so the lights were all dimming. We were able to push the car home (it broke down a minute away from our house) and when we get it there, the lights were all bright again. This led me to believe that the problem isn't from the alternator. It doesn't sound like the starter is moving when I try to start the car.

A few days later, I decided to go poking around and see if I could find any clues as to what's going on. I disconnected the battery for an hour, tried jumping it again, nothing had any effect. I checked the codes and it was giving some random code that I forgot but I can check again. When I checked the iDrive, it was throwing a bunch of errors. One was for the suspension, one was for the passenger restraint system, and another was for the battery. When I clicked on the error for the battery, all it said was "Masterdummytext" (I included a picture of it)

A video of me trying to start the car

First guess is bad alternator, second is battery cable to fuse box is degraded.

Same thing happened to my brand new 09 e92 m3 many years ago.
Turned out that it was a loose negative battery cable.
Tightened it up and never had that problem again.

Thanks for the replies.

Datka wrote

Same thing happened to my brand new 09 e92 m3 many years ago.
Turned out that it was a loose negative battery cable.
Tightened it up and never had that problem again.

This was my first thought. I tried tightening up the battery cables and tried cleaning the leads but it didn't help.

msan wrote

First guess is bad alternator, second is battery cable to fuse box is degraded.

Do you know how I can test the alternator? The only way I know how to test the alternator is if the car is starting. Also, do you know where I can check the battery cable to the fuse box? Trying to diagnose this car makes me miss working on my E30

haseeb1898 wrote

Thanks for the replies.

Datka wrote

Same thing happened to my brand new 09 e92 m3 many years ago.
Turned out that it was a loose negative battery cable.
Tightened it up and never had that problem again.

This was my first thought. I tried tightening up the battery cables and tried cleaning the leads but it didn't help.

msan wrote

First guess is bad alternator, second is battery cable to fuse box is degraded.

Do you know how I can test the alternator? The only way I know how to test the alternator is if the car is starting. Also, do you know where I can check the battery cable to the fuse box? Trying to diagnose this car makes me miss working on my E30

The battery cable fuse box is behind the glove compartment. Check out my DIY for further diagnosis.

http://www.m3post.com/forums/showthread.php?t=1357407

So I tried replacing the fuse box cable and tried using another battery but it's still not working. Is there a way I can test the alternator to see if it's working properly?

haseeb1898 wrote

Thanks for the replies.



This was my first thought. I tried tightening up the battery cables and tried cleaning the leads but it didn't help.



Do you know how I can test the alternator? The only way I know how to test the alternator is if the car is starting. Also, do you know where I can check the battery cable to the fuse box? Trying to diagnose this car makes me miss working on my E30

Check out my topic for that.

http://www.m3post.com/forums/showthread.php?t=1142234

If you can find someone who has DIS or ISTA you can easily see the live values of any electronic module so you know what is working or not!

haseeb1898 wrote

So I tried replacing the fuse box cable and tried using another battery but it's still not working. Is there a way I can test the alternator to see if it's working properly?

My understanding is the fuse box +B cable issue will only be prevalent when the car has no power (lights, comfort access, etc).

Did you check the engine-to-chassis ground cable? They can become corroded and it is located on underneath/backside of engine. You can also try using a jumper cable to "ground" the engine to the chassis to prove this out.

Do you have access to INPA or a bmw-specific diagnostic tool? There will be faults stored in the DME that do not always show up on a generic scan-tool.

I'm going through similar issue right now.

SaNGRia wrote

Check out my topic for that.

http://www.m3post.com/forums/showthread.php?t=1142234

If you can find someone who has DIS or ISTA you can easily see the live values of any electronic module so you know what is working or not!

Car died while driving which should rule out clutch switch issue but yes, your methodology and persistence to root-cause analysis is inspiring!

haseeb1898 wrote

So I tried replacing the fuse box cable and tried using another battery but it's still not working. Is there a way I can test the alternator to see if it's working properly?

You could use iCarly and monitor the voltage while driving to see if it is low or below normal levels

Mine did very much the same thing. I went through the same process, replaced the battery free under warranty. Same problem. Changed the alternator because it was not putting out the right voltage. Solved the problem.

I don't remember the sequence but the dash panel info can tell you voltage output.