When my battery was weak after having work done with doors open and lights on, I got the 4X4 light and when checked with my NT510 I got the steering angle sensor fault. A good charging of the battery solved that problem, but my battery is less than two years old. I'd go with the battery first. BUT, there are many on here who know more than I. See what else is suggested here, I'm sure an expert will jump in soon.