There's a guy that repairs the modules out there in the inter webs…ahhh, here's his site:

GM3 repair

I sent him a question about the GM5 module in my wife's E46M3 regarding an intermittent door lock problem we were having. He could have said to just send him the module for repair, but instead he directed me to a more likely cause. Based on that alone I have to say he's worth sending an email too describing your issues. Good luck!

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Kirk
Las Vegas
2016 X5 40e Mineral White/Black Dakota Leather, ZLL, ZCW, ZDA, ZDB, ZPP, multi contour seats, rear side window shades, HK stereo
2011 E90M3, 6-speed manual