I have a 2015 Cooper S F55 that has been running great until yesterday. I was driving the car and stopped at a light and the auto start/stop switched off the engine. When the light turned the car would not restart. The dashboard will only flash briefly and then shut off. I still have power to the interior lights/chimes and windows. I replaced the battery with no change. I pulled and tested all the relays/fuses and they all seem fine. Any ideas what might be causing this?

 

When you replaced the car battery did you code it? It needs to be coded to tell the car the battery is replaced.

Also with an OBD2 reader you can pull codes.

 

The ignition will not say on to be able to connect to an OBD reader or to ISTA to code the battery. When I hit the start switch the dash flashes and the fuel level lights go up and down and then everything turns off again. This is with or without the clutch engaged. I tested the old and new batteries and they were both functioning normally. All the door locks and interior lights work. I can here the fuel pump prime when I get close with the key fob. The fuse panel is getting the correct voltage. I’m starting to think the start/stop switch console is shorting or something.

 

I would start with the start/stop switch console too. If that's not it, then move onto the starter. Good luck!

 

Sorry for responding on an old thread but i'm having the exact same issue on my '17 F55. Did you ever figure this out?

 

Check your grounding strap. It gets corroded and doesn’t carry the ground current. Replaced it with some heavy gauge wire and it started right up. Had this happen on both my ‘15 minis.

 

Thanks! Its currently at the dealer (not MINI, just the dealer i bought it from) since i have a 3000 mile drivetrain warranty with them. I called and asked them to check this and they claim they already did. I'll go out there and drive the point home or, just collect the car and fix it. Much appreciated!

 

Bingo. Car is fixed and it was a chassis ground strap. They aren't even charging a diagnostic fee since I told them the diagnosis. Thanks again!

 

Kudos to this thread. Wifes newly acquired F55 randomly died in a parking lot. Went out to rescue her and was baffled by what i seen.

Hit the ignition and every light came on, it wouldnt start and kept saying put vehicle in park (it was), it was flashing errors of chassis stability mode activated, visit service center. The car would also not stay in accessory mode and i had to rapidly press the ignition switch to get the dash to stay light up. Hooked up my OBD blue tooth dongle and i couldnt actually read the car, bimmercode would get to about 22% and kept getting errors. Baffled by this i checked the battery voltage which was at 11.9v. Called a tow truck and brought it home.

Upon getting it home, battery was still at 11.9. The electronic coolant pump was running constantly, so i had assumed now that this pump had failed and drained the battery causing all these electrical issues. Problem was i couldn't establish any connection to the car with the bluetooth dongle, bimmercode obd to enet cable, and standard scan tool. Knowing how finicky BMW is with low batteries i stumbled upon this thread looking for answers beside battery drain. With this hunch i took apart what seemed like the entire engine bay, removed the ground strap and seen tremendous amounts of fraying. It wasn't broken through but looked like it was making half its original connection. Drove into the auto store, purchased a generic $13 ground strap. Every issue went away, car fired right up. Had to clear a couple check engine codes but none returned.

Thankful for this thread leading me to the ground strap!