e60 m5 died after jumping semi truck

[sjzking408]

Hello everyone!

New member here. A few days ago a good friend of mine called me to help him jump start his semi truck (2022 Freightliner Cascadia). So me being obnoxious went to go help him since he was close by in my city. So the semi truck has 4 batteries. I took out a heavy duty jumper cable. Popped my hood. Connected the jumper cable to the red positive + Lead. My car is a 2006 m5. So we tried starting the truck like that but it wouldn't start.

So then we put the jumper on each battery for 10 mins (totaling 40 mins) as someone had suggested, but that still didn't work.

Then someone called him from his company and told him instead putting the jumper wires on the batteries, pop his hood open and connect it to a main + lead on the frame (similar to the one on the m5 engine bay). So we did that and the truck fired up instantly.

So while I was driving home, about 10 mins later, on the mDrive screen first I had a transmission fault. Then the car would get out of gear and just go into Neutral. It did that several times until the car just died. Pushed the car off the streets into a parking lot. I called AAA roadside service. They tried jumping it, it wouldn't start.

So AAA roadside ended up towing the car to my house. The AAA rep suggested that I probably burned my alternator.

This car got a brand new alternator put in about 1.5 years ago from a private shop.

What ya'll think happened. Did I burn the electronics in my car?

Please help!

[PaisleyFontaine]

The m5 doesn’t not like to give or receive jumps, and doing so requires a few more steps than just clamp and turn.

Owner's manual gives instructions on what to do if need to jump or give a jump:
-turn blower motor on high
-turn rear window defroster on

It goes on to say that the high electrical loads from above dampens potential voltage surges.

[sjzking408]

hey guys! Sorry finally had time from work to work on the car today. Battery was completely dead; had to open car manually with key, pop the rear sears and pull on the trunk release wire.



So purchased new identical battery from AutoZone. Replaced battery and programmed new battery (via Innova 3215RS) checked on manufactures site and it showed it's compatible with my 2006 bmw M5. Went through all the commands and showed new battery was programmed to car.



Still the car does not start. It's not showing any codes in the scanner or the iDrivce. Also tried disconnecting the IBS wire from the negative terminal; still no start.



Any fuses or realys to look for?



I contacted a independent mechanic that had worked on this car few years ago and told him the issues; he said he wanted to put new battery and alternator regardless. I asked him if he could just replace the alternator regulator. He insisted replacing the whole alternator. This car had a new alternator replaced about 3 years ago from the same mechanic.



Please help. I have free time now from work. And now I have made it a mission to fix this car!!!

[Simpletools]

sjzking408,

Semi Trucks are not always 12V systems. Depending on the model that you jumped, it may have been 24V or perhaps is 12V with a 24V starter. That means once the truck started or during the start, your car may have received 24V or more.

This may be the cause of the electrical issues on your car. I would start with identifying the model of truck that you jumped to rule this out.