[emhtuning]

Hello ,

there are tons of threads and youtube videos on how to register a new battery , and we've been doing it for years already for Exx and Fxx .

today I came a cross a new topic which I've not seen anyone talked about it before.

BMW E91 with original 90A battery and auto start/stop option, the owner had big sepakers and 2 subwoofers sound system and Xenon fog lights installed so he wanted to change the battery and upgrade to a bigger one at the same time . he ordered 110A Varta AGM battery , we did battery amp change then complete car coding , then we did new battery registration and everything went smooth . after 3 days he called and complaining about auto start/stop never works again after the new battery. we spent half day testing and trying different scenarios and we did compare with another E81 car with auto start/stop . in many scenarios the E81 switch off the engine while the E91 stays up and running .

then we decided to swap with the old battery , and immediately the auto start/stop works again.

my question is not about what could be the problem , it could be many things .

my question now is , is there procedure to delete the new battery registration. ?