Battery Problems of BMW 750

This vehicle model with the v12 engine has a system that heats the catalytic converters shortly after start to reduce tailpipe emissions during cold starts. This system is known by BMW's trade name of ecat. The system is powered by the starting battery (BMW v12s use two batteries - one for starting and powering these high-curent ecat heaters; the other battery is used to power all other vehicle electrical loads like hvac, entertainment, power windows etc. The v8 and i6 model Bmws do not use this system. On Tuesday, 12/13/2011, I got in my car after it was sitting all day in the parking lot at work and as soon as I opened the door, I noticed a strong burning electrical smell. After some investigation, I noticed the smoke was coming from under the passenger seat. After checking with some BMW-related message boards on the internet, it seems this has happened a number of times on this model of BMW. The exact problem is the ecat control module located under the front passenger seat. This module controls the high-current catalyst heaters described above and in my case, the module developed a short and became quite hot - hot enough to fuse the high current leads to the module, and melt the carpeting above the module. I believe this to be a profound safety of life issue, as if I hadn't disconnected the batteries right away, the vehicle could have caught fire. I believe this issue warrants a manufacturer recall.

See all problems of the 2001 BMW 750 🔎.