When you replace a battery, you must "code" it to the car. In other words, tell the car the exact CCA of the new battery. I assume this can be done with GT1 but I know it can be done at a BMW dealer or with an Autologic. This is essential for any BMW newer than about 2006 or 2007. The car will NOT automatically adjust to the new battery.

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2014 BMW 328i Xdrive
2011 BMW 335i M-Sport
2008 BMW X5 4.8i Sport
2000 BMW 528i 5sp