Does this happen at a particular speed or any speed?

 

I have a 2004 XJ8 with the exact same problem. This issue has been reported by numerous owners, however, I have yet to read of a solution to the problem.

There is coverage of it on http://www.dandmbr.co.uk/jaguar/. I didn't have time to go thru and find the thread. Again, no solution found.

On my XJ8 it normally happens between 60 and 80 kms/hr when the car is cold and coasting at a steady speed on the highway. Many owners have simply decided that they can live with it and unfortunately, I gave up on trying to find the repair.

If you do find a solution plse post.

 

2004 VDP same issue. I usually drive around 30-35mph for about a mile, when leaving home in the morning - happens in the middle of the strip. I have also observed it at higher speeds ~60MPH once - again the car was still cold.

My transmission ECU was re-flashed about 8 months ago to fix the shift adaptation logic. I don't know if both are somehow related. I don't know if the engine ECU was also updated.

 

There is a special CODED reflash for the transmission control module that fixes this problem. I'm not certain it is available outside the U.S.

 

So I can go to the dealer and they can fix it, cool. Is there some TSB or something I should mention to them, in case they can't find it?

What exactly is CODED reflash?

While we are discussing trani issues, I have another minor one: If I switch from reverse to drive and press the gas immediately, the engine revs up and I get a very hard kick after 2-3 seconds. If I wait for about 5 second, not rev-ing the engine, it shifts smoothly. I dont think it matters if it's hot or cold for that one. I'm very light footed, not that I'm flooring it when shifting to drive.

 

I have the same issue and somewhere on this forum it was brought up that most likely we will need a new torque converter.

 

It is called a CODED reflash because during the procedure the IDS will generate a special code that must then be relayed to the Jaguar technical help line and the help line will give a response code that must be entered into the IDS for the programming to take place. This reflash fixes the rpm surge and hunting and yes there is a service bulletin about it and any time you do a reflash of a 6 speed transmission module the IDS asks you to choose either NORMAL or CODED in one of the first steps so ignorance is not an option.

The reason for the code is the parameters changed to correct the hunting/rpm surge also alter vehicle emmissions and all cars that get the coded reflash have to be reported to the government.

How would anyone know whether a torque converter is needed if you don't know whether the coded reflash has been done? The reflash is a lot cheaper.

 

2004 VDP same problem. When cold the tach will bounce a 100 or so RPM's. Had the TCM reflashed by the dealer and when the car is warm or it's summer there is no problem, but when it got cold the problem came right back.

 

its available outside the U.S. and it fixes all the problems.. but has to be done at a dealer