Not an expert by any means but had recent issues related to the OPs:

1. Had the low speed knock and after some suspension part replacements it turned out to be that sway bar link - can’t confirm if it was just loose or needed the replacement but definitely was the fix. Hopefully you’ve found the cure as well.

2. After hours of ccv, pully, and alternator replacements last week, I got the trans fail safe error on my first start until i realized i hadn’t plugged in my MAF connection. Not saying it’s the connection but hopefully related to the MAF and you fix two birds with one stone.

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Silver 2006 BMW X5 3.0i Auto