Hello, On our 2018 X1, we are getting the SOS System Failure warning. It's well known that this is usually the battery in the system requiring replacement. In our case though, the problem disappears in warmer weather, sometime for a short period in cooler conditions. I feel that this is unlikely to be the battery, more likely a connection fault. I have limited faith in my local BMW dealer. They will .almost certainly want an hour to diagnose (£150+) and the pronounce that the system needs replacing, at a cost of thousands.