Since the winter, my AS module has thrown a bong and "Active Steering system fault!" has appeared in the display during virtually every journey. My BMW mechanic diagnosed the module as faulty while doing other, more pressing work and claimed that my failed alternator was the root cause, saying this module is particularly sensitive to voltage errors. With charging restored and the recently replaced battery tested and in order, I postponed dealing with the AS and lived with it for another two months.

But during the last week the fault hasn't appeared and the steering works as it should. That's after five months of issues. I've sourced a replacement module but is it realistic to think the old one can be relied on again?

 

My guess is that it's warming up in Norway, and that you might well see the problem come back when the sun disappears and it gets cold again (aka "thermal intermittent issue"). Hope not, but for now it seems like there's no big down side to taking a wait-and-see approach.

 

I would not worry about it unless it happens again.

 

Well, as I dreaded it's started happening again, every fifth journey or so. So it's not a thermal issue (it's even warmer now) and it clearly won't pick itself up by the bootstraps. Replacement module to be fitted, next.