I have a 2.1 litre petrol X-type that has developed into limp mode after a gearbox error. Our local Jaguar garage has checked the wiring and says it is a error in the gearbox.. A nearby gearbox specialist says that it is not, and will be an electrical problem , leaving me very confused. I have been told that the problem may be the TCM, but nobody other than Jaguar themselves seems to have a matching TCM. Mine is 2x43-72401-JA but the only 2nd hand TCM I can locate has -JC instead of -JA. Is the difference significant? A new TCM seems to be £800+, and the car is only worth twice that, and I cannot be sure that it will solve the problem. Any help welcomed.

 

I have at last been able to get a specialist Jaguar repairer to have a look at the P1643 problem, which they traced to the chirp sounder, which now it has been disconnected resulted in both the ending of the headlight problem and the limp mode 'Gearbox error' problem. Still need to stop the door latch problem and fix the brake light issue (at least I still have one that works).
What concerns me is that the P1643 error intimates that it was a ECM to TCM communication problem when that was not the cause.