Collectively, we all pay at least lip service to the forum-wide mantra of "It's The Battery, Stupid". But individually some of us (like me) fall prey to denial when it comes to specific problems.

"There are no other symptoms/codes/issues"
"The battery has been load tested"
"There's X voltage coming off it" etc.

I had always had an intermittent AFS warning light, once a week or so. There was NOTHING else amiss; no codes, nothing else wrong, no poor starting etc. I decided it was a poor ground, or flaky insulation in the headlamp, or a bad module. Since it always cleared after two drive cycles I never got round to fixing it.

Then recently I decided to replace the battery. There was nothing apparently wrong with the old one; it was a pro-active maintenance decision on a car I didn't have full history for.

Since then, I have driven at night, driven in a rainstorm, had the car pressure-washed, had it sitting with the doors open all afternoon while it was detailed - and every other kind of indignity possible for the car, and the AFS error has NEVER COME BACK. The only thing that's changed is the battery...

ITBS indeed.

 

Possibly a Hard Reset would have also helped? You know, since Battery Disconnected and all that...
Just a possibility, I don't recall if you've tried that or not previously.

 

Now you know how sensitive the X150 modules are to a low battery, and why it's a good idea to have a battery maintainer that'll keep it fully charged.

 

Ahhh. Should’ve read this thread first…

 

See Post #16 in the below thread to add an ITBS Smiley to the existing list :
https://www.jaguarforums.com/forum/x...isplay-282394/