I purchased my 2008 XK earlier this year with only 35000 miles on it and in excellent condition. I had noticed early on that it had the harsh 2-1 downshift also referred to as the ZF lurch.
By doing a couple of things I have made it much smoother and can actually drive around it for the most part, but occasionally I will feel the downshift coming to a stop.
I have also read many threads stating that it is definitely a software issue and that a reflash of both the ECM and TCM with a drive cycle afterwards will eliminate the issue.
Here's my question, I called the local Jaguar dealer this morning and went through this and he is aware of it, his comment was that because of the age of the car there is a possibility that it will brick the transmission. He stated that he has done some and it worked perfectly and others where he couldn't back the car out of the Bay when they were done.
It certainly isn't worth taking that chance if this is the case but I'm not sure what the age of the car has to do with a software reflash?
Any input would be appreciated. Thanks

 

I'm am far from an expert in SDD and flashing modules, but I don't think I would take my car back to a dealer that admits to bricking cars doing what should be a basic job for them... Sounds like they just didn't want to do it or have very limited experience with these cars, either way I wouldn't be taking my car back to them. You should find a different dealer to work with. You could also PM someone like Cambo for advice, he is very knowledgeable on these subjects.

 

Thanks.
Agree completely, and won't be going there for any non-essential dealer service.

 

Are these 'downshifts" happening in DS mode

 

D mode and DS. Different speeds while slowing down though. In D only as rolling to a stop from 2nd tp 1st, in DS starts from 3rd to 2nd then 2nd to 1st.

 

The issue with your car, my car and your dealer statement is this. Many times people call a dealer and want a trans drain and fill, and or reflash. Usually because there is a issue. Then after we do said work theyre in the directors office complaining about something now going on with trans "after" we did whatever. Not saying you will or would what im saying is thatthe public out there does target deep pocketed dealers as a transmission is expessive period. We had a director that said if we did flashes or services and something happens we could pay for it. So thats the issue is the market, people talk about ***********sss but they are people that come in for these reasons. They wont go to indies because theyre gonna tell you to pound sand. The money made is minimal compared to pontential liability. I have a 04 vdp and do my own flashes and drain and fill evey 60k. I just turned 196k same closed engine and transif you look on amazon there are several products for squawk/shudder like lucas and a couple others i would try. We used to put a additive in trans in addition to software updates. And we still do them but not for people that are not regular customers because of what i said before. People come in for a issue then want to hold us responsible for a negative outcome. And that you will never sell enough flushes, updates to overcome that hit on the bottom line. As a former full time and part time business owner i would have to agree with this stance. Hell my ex couldnt even get her oil changed on a volvo years ago because she had over 200k and the shops didnt want to touch it

 

Reflashing is not always simple or effective.Anything beyond hooking up a battery maintainer when flashing and following the directions on the screen is out of control of the Tech.

Sometimes software has a glitch and the module won't accept the new program. Sometimes there is a fault in the module.

Sometimes the electricity to the computer will feel a surge in power and abort in the middle.

Those things are out of control of the Tech or the Dealer, that's why they warn against re flashing older vehicles and leave the choice up to the owner whether or not to risk it.

 

^^^ and loss of internet connection in the middle of downloads. These are all real world issues we face.