All right guys I need some help. I have a 2004 jaguar XJ8 the other day gearbox fault turned on after a little bit of rain, I’ve had it do this before but it generally shuts off after A little bit of sitting. As of right now I’ve had gearbox fault on for three days. I haven’t drove it I’ve tried unplugging the battery and letting it sit. I’ve checked fluid level and as soon as I start it back up, The very first thing that comes on is gearbox fault that’s with no shifter movement nothing. I checked the shifting linkage on the side of the trans I’m currently checking the J gate, what am I missing I would think it’s got to be some sort of electrical problem and I have no idea where to begin. Any help would be greatly appreciated Thanks again

 

I'd start by pulling codes and posting them here.

 

When was the fluid and mechatronic sleeve replaced last? The sleeve itself can leak if not replaced, causing erratic faults until it simply remains in limp mode. Other than that, check codes and it could lead to something else that is causing incorrect values between fuel management and a sensor. Ive had Throttle issues on other cars which in turn caused the transmission to go into limp mode.