My 2000 model XKR soft top suddenly developed a dash fault - No guages or dash lights and gearbox inactive, heater not working. I checked fuses and connections as I could find them but no progress. a "hard" restart got them working on two occasions but a second start they would be inpoerative again.I sent the instrument binnacle away for a refurb and after checking it i was told it was fine. While it was away I replaced some coil packs with genuine second hand ones (as they were rusty) and I disconnected the air flow meter to do this. Refitted everything and the dash gauges now work (who knows why now) but i get a PECUS T error message on the dash plus red and amber flashing warning lights. Car runs fine but In have not driven it.
Lastly, my windows need to be reset every time I use them which i've been told might be a voltage issue.
It had a new battery only six months ago and the voltages across it look good.
I have no idea which of these issues are relevent to each other if at all.
I tried a "Hard reset" by disconnecting the live and negative battery cables together for 30 mins but cannot get rid of the PECUS T message.
It looks like an electrical or coding bug to me. I cant believe the transmission has real issue.
Any ideas from forum experts?

 

I would attempt to communicate with the gearbox module to see if it is 'online' and alive on the CAN bus.
Check for DTCs if it is communicating.

Check the CAN bus for continuity?

 

At the risk of sounding just like a broken record, Are you keeping a battery tender on your newish battery when the car will be sitting overnight or longer ??

these cars have proven over and over they are ridiculously sensitive to battery voltage. If you take some pressure off of the charging system by using a battery tender many of these electrical gremlins will vanish.


Z

 

What is the actual number "across it"
Needs to be minimum 12.6 volts rested to stay out of trouble.