I recently removed fuse 19 to disable the active exhaust, and then a couple drives later, I noticed that in both manual mode and sport mode (auto), the transmission would not rev match downshifts. Rather, it would be like any other automatic where the momentum of the car would sort of increase the revs while downshifting. Also, the manual shifts would be quite a bit slower and more jerky.

I thought maybe removing fuse 19 was the problem, but the next two drives, everything was perfect with throttle blipping and rev-matched downshifts.

Any idea what happened? Is this anything I should worry about?

Thanks!

 

By the way, there were no transmission faults displayed or CELs on the instrument cluster.

I'd like to make sure this doesn't happen again as I did an aggressive manual downshift before some moderate braking leading into a curve and it damn near sent me into the curb! Thank god I had traction control on!

 

Just for my information, why would you disable the active exhaust?

 

https://www.jaguarforums.com/forum/x...se-19-a-87400/

Has anyone else experienced what I just described? Sometimes the transmission will not revmatch downshifts?

Could anyone describe the mechanism that is used to rev match the downshifts in manual mode (and in sport mode)? Is it purely controlled by ECUs, or could it have been affected by my pulling Fuse 19?

I haven't had this problem since it occurred the other day, but I have only driven it twice since then.

 

Hmmm... drove it this morning--rev-matches fine. I hope this was just a fluke!

 

I've had this problem periodically since I first bought the car. 5 years and 9,000 miles later it still does it once in awhile but after I restart the car it back to normal.

 

Oh good, I'm not the only one. Any idea what causes the problem? My XKR is Select Edition so I'm wondering if it's worth taking it to the dealer.

 

Not sure but once in a great while when I use the paddles it doesn't rev match. When I told my dealer the first time it happened, they need to see it to do anything and of course after a restart the rev matching works again. It happens appox 3-4 a year but again I only drive the car about 1900 miles a year althought 95% of the time I do use the paddles. When it doesn't rev match it's quiet when up or downshifting with occasionaly abrupt jerking when downshifting. Feels like the tranny went into limp mode.

 

My "guess" is that your transmission is briefly in a "relearning" process. For instance, whenever you reboot your ECU, your ECU "relearns" the peculiarities of your specific drive train. The clue to me is that eventually the problem is self curing, which is indicative of a learning process.
That's why it is frustrating to take the car to a dealer as the dealer cannot then duplicate a problem, which has cured.
It may be that long inactivity or just changing a fuse (#19) can trigger a relearning process. That is just my guess. But if the condition persists and does not self cure, then you have an actionable problem.

 

That does seems plausible--the transmission relearning. The problem has not come back. But unfortunately, it has shaken my confidence in the revmatching of the manual mode, so now before I get crazy, I always do a test manual downshift!!

 

Happened again today. It seems like it is a faulty battery, without doing any tests--just conjecture. I notice that after I restart the car, the screen goes from dark to the menu screen almost immediately, but the first time in the morning when I start the car, especially if it's cold out, it can take 10-20 seconds to do it.

After I restarted the car, it worked like normal, though.

Does anyone know what the battery voltage should measure?

 

Bah, now it's happened about 4 times since I first posted this. Unfortunately, it's sort of intermittent, and restarting always cures it. It's strange though, because I can start a drive and have the rev-matching work, then the revmatching will suddenly stop functioning properly. Then I have to restart and then the revmatching will work for the duration of the drive.

I noticed that at the beginning of this particular drive, the car gave me a warning about not being able to connect to my phone (but eventually did connect). I imagine this is another sign of a bad battery.

I want to have my battery tested. How many volts is it supposed to read?

 

Hmmm... it did it again today on the way home from work, just 4-5 hours after it last did it. Then when I got home, I shut the car off, out of curiosity. I tried to restarted the car, and it wouldn't start. All the lights would flicker on and immediately cut out. This happened 2-3 times. Then I waited a few seconds and tried it again, the car started right up.

I went for another drive, and the rev-matching was fine. Then I came back and tried the same thing, shutting off the car. Each time it started up perfectly fine. It's entirely possible I didn't push the button down all the way. In fact, I'm sure that's probably the issue with the not starting.

 

Still experimenting here, but I think it's definitely battery related. I was driving it perfectly fine today with the manual blipping downshifts, but then a minute or so after i turned on the seat heaters (high battery load), the transmission went into lazy mode.

 

I posted this in another section as well:

I had the same problem on my 07 XKR. I've now traded up to a XKR 175 so I hope the problem is not still experienced on 2010+ models. Anyway...my dealer had me bring in the car when the regional Jaguar rep was in town. We drove around while the rep had a laptop plugged into my OBDII port. Jaguar suspected that the car was overheating and going into limp mode, but this was WRONG.

The car was not overheating. Instead, as one member pointed out in an earlier post on this topic, the transmission model simply gets confused as to the proper shift map. It's entirely software related. (That's why restarting the instantly car fixes it, even without having to let the car cool down.)

My dealer ultimately fixed the problem by erasing the transmission AND engine control modules. They then reinstalled the software for both modules. This, of course, leads to a host of other software problems with other modules. But once they updated all of the software, then the car worked fine. I had a CPO, so it was free to me. They estimated about 10 hours of work after the problem was diagnosed, so here's hoping you have a warranty...at local rates, I would have been out almost $1500 if not for the Select Edition warranty.

 

Jeeze. I did not realize that the problem was so expensive to fix! I thought it was going to be a simple reset of the transmission adaptations.

I have brought the car into the dealership TWICE for this issue and first they told me they couldn't reproduce the problem. Then the second time they gave me an excerpt from the owner's manual, telling me that the car was working as designed.


In the video, I am not using any brakes. Yet when I downshift into 1st, the engine does not blip the throttle. The car rapidly slows down and then the shift completes.

Compare that to this, which is how it's supposed to work:


Clearly it is not working properly. Is there a way I can actually get my dealer to do something about it? There is another Jaguar dealer in the area but it's the same chain. A third dealer in the area doesn't seem like it'd be any better.

My Select Edition warranty runs out in about 1 month!

 

I hope you got these things fixed and that they help you find a cheap solution you deserve it. I will go to the third one if I was you.

is there many amg battery, are they any better finally? as it does not seems now...can't you take it back there for a refund? and install a oem jag one. Mine seems to last...

 

I initially took the car in just to have them reset the adaptations. They wouldn't do it under warranty, and because of the CPO, I wouldn't pay. I was able to reproduce the problem consistently for the techs (while they were in the car), so they just assume the modules needed to be replaced or reprogrammed.

We had the OBDII computer plugged into a laptop while driving around (difficult because it records only for a few minutes), but we demonstrated for Jaguar that it had nothing to do with overheating, etc. It was definitely NOT mechanical. It was only then that Jaguar agreed to pay for software/module reprogramming or replacement.

For what it's worth, I still think the adaptations are at fault. Jaguar just wrote bad software, and they know it. And I think it needs to be cleared once and a while.

Jaguar dealerships are getting worse than Lexus dealerships -- they purposely stare at you like you're stupid and then tell you that your car is acting normally even though you've owned and driven it for years. One of the techs at my dealership admitted that he never drove an XKR (only XKs) and that he was just told by Jaguar to tell me that it's normal.

 

it's sad sometimes, once i had the problem with the 2007 facelift and jaguar france never helped to diagnosed it, due to the arden (nightmare) module installation to lower the vehicule, jag france agree about it, then backed up, one time they agreed for a tow away and service paid under warranty and finally billed me for 800 euros. while i was struggling with 3000 euros of charges to try diagnose the problem and it took me so much time that when it was fixed, i was totally pissed off of the car and sold it. I called jaguar uk during the problems and I fell like I was calling a different brand, or that i was in the moon...They really didn't care at all and send me back in the hands of those idiots of jaguar france.

If there was a problem with the warranty, they should at least be able to diagnose the problem, expert 1000 euros, 4 dealerships 2000 km driven for this or more etc, for 6 months or more..(arden module advised and installed by a jaguar dealership who ended up filing a claim against me! Jaguar Lyon Automotion, a real bad dealership with corrupted people)

Honestly how many other people will never buy a jag after this....

It definitly takes more than passion to over pass, what others makes you feels, how ready they are to break your feelings.

Sometimes finding the right dealer or changing in time! as things goes like this and there is nothing better than changes sometimes,
I meant all is in the hands of the dealership service manager, how willing he is to do things for you OR not?

 

How long does resetting the adaptations take? Would it really be necessary to reload the engine control software as well? (Could I try having a shop/dealer reset the transmission adaptations first?)