2005 xj8L with about 250k miles.

During and after rainy weather the transmission feels like it randomly shifts to neutral for a moment. I also may get restricted performance, Gearbox Faults, and code P1643 which is a ECU TCU network communication error.

From searching the forum it seems that some people have success correcting this issue by Removing the ECU, drying it throroughly, and making it water tight. I plan to try to waterproof the ECU this weekend.

I have also seen posts where it is suggested to "check the electrical connection at the back of the transmission for water", but I haven't had any luck locating this connection. Can anyone point me to the specific location of the trans electrical connection or to an exploded view of the trans with the location of the connecter?

While I'm at it, are there any other suggestions regarding anything else to clean and/or water seal, related to the ecu tcu can error? Wiring harnesses, relays, ground wires, etc? Locations of those suggestions?
It already has a new battery

Thanks

 

Victor,

My 05 Super V8 with 109k sometimes exhibits similar behavior. I never associated it with wet weather but it could be so I will have to watch for that. My car only misbehaves when asked to shift down at highway speeds (above 50 lets say). It will pop out into neutral under heavy throttle while the rev needle goes right to redline and then it usually goes back into a very high gear but sometimes it just stays in neutral till I let off. Needless to say this is extremely unpleasant and disconcerting. Only rarely will I wind up in limp mode. The trans fluid was changed by a Jag specialist at 102k miles and the battery is new.

Last time she threw one of these fits I read the following codes: P1774 (CAN timeout - J-Gate module malfunction) P1799 (CAN TCM / ABS control module circuit malfunction) U2012 (CAN communication fault Dynamic Stability Control) and U2522 (CAN message timeout from TCM). She went into limp mode locked in one gear until I shut down and restarted, and then things were fine as long as I didn't ask for a kick down. Other days everything is fine.

I have on my to do list to clean all the headlight grounds. Maybe I should climb under and check the shifter cable bolts on the trans and the trans electrical connector? I've also wondered if it might be wise to have the dealer clear and update the TCM .

Best Regards
Jeff