I have had an intermittent High Gearbox Temperature failure for a few months (no rhyme or reason to it appearing - except NEVER when I drive the car, only when wife and kids do!). Just figured it was sensor and car always starting after sitting.
Yesterday, however, after sitting for 5 hours, it still threw the High Gearbox Temperature Message and Engine Failsafe messages - but it cranked and cranked and cranked and wouldn't start.
I pulled the positive lead off of the battery (I forgot to touch it to the negative terminal so I guess I did not do a hard reset) and the same problem remained.
I thought the car should at least start? I am going back today to do the reset and try it again.
Thanks !
p.s. Yes, I am once again going through the ODB code reader thread. I know that someone must have posted a reader for my XJR.

 

Have your referenced this.... JagRepair.com - Jaguar Repair Information Resource

 

Thanks for the link, though quite frankly it is above my very limited abilities...
Anyway to my surprise, I went to try it today before having it towed. The warning messages flashed again, she cranked the usual 3 or 4 times, and then she started! The messages disappeared. I drove home and do believe the transmission was shifting (by tach, as I took back roads and never got above 50mph). When I got home, I tried it a couple more times and it started cleanly with no messages. Oh well. Thanks for the help. Hope to get it to the dealer ... and to actually purchase a code reader that works with the car!

 

Its standard OBDII, nothing special

 

I'd find a jag indy as they will more likely have a clue about the whole car including the trans.