First off, I love this forum! I'm extended testing driving a friend’s 2001 XKR and fixing some things "prior" to purchase so we could stay friends "after". The expertise on this forum has been invaluable (I've used it extensively)! I decided to join the forum before even buying...

Second, I love the 2001 XKR! What an amazing piece of art and performance. I'm learning what the XKR likes and how to drive it, and it is reciprocating with giving me a big smile even on the simplest of drives! :-]

So, I'm on the last major issue to fix before buying. I get a Restricted Performance message when using the J-Gate on the manual side and it happens in either Sport or Normal mode. My manual side J-Gate has "2 - 3 - 4" before sliding back over to the automatic "D". When initially shifting to 4, there is a spring tension that wants to take the shifter right back to D unless I hold it at 4 (owner said the springing back was the correct behavior, but that doesn't make sense to me). If I have downshifted further into 3 or 2, sometimes when I get back to 4, there is no longer any spring tension that wants to take it back to D (but not always), and it stays in 4 unassisted sometimes. I believe this is when the Restricted Performance occurs, when it stays in 4 instead of springing back to D. What is the desired behavior of the J-Gate between 4 and D since I get both behaviors?

I have already had a couple of pre-purchase inspections and pulled error codes, and this current failure doesn't have one. I had some temp sensor error codes that were cleared when we replaced the battery that was drained last winter, but the manual shift problem still exists. I even created the Restricted Performance prior to a tech looking at it, and there were no new error codes. After new battery, I did a hard reset to clear everything out of the ECM and took my time with the ECM learning, but the problem was still there once I used manual shifting again.

I've searched the forum for this specific issue but have not found it yet. Has this been diagnosed and fixed by someone already?

Does anyone know anything about TSB 303-49 Restricted Performance Displayed on Message Center - Limp Home Mode - AJ27 SC Engines - Reflash ECM? It falls within my VIN range. And it seems to be a TSB that occurs without a specific error code. The tech at one of my pre-purchase inspections found it and suggested it, but I would like more information on the TSB first. And I wonder if this TSB calibration will fix my issue? What is it calibrating? Mine seems more related to some gearing, sliders, or sensors for position 4?

Thanks in advance!

 

I can only answer the simple question. If you are in 4th it should stay there. When I'm driving back roads quickly I've never had it pop from 4th to drive by itself.

 

It does sound mechanical.
Here's a thread with some useful info to help you have a look at the 'works'.
https://www.jaguarforums.com/forum/x...working-84969/
Not hard to do.
Can't help with the TSB - but if it has been done there should be a label
Enter your dealer number and the date on the Authorized Modification Label as shown
Write in “Reflash per TSB 303-49.” Apply the label to the driver side B-post below the door striker plate on XK8 vehicles, and next to the left hood hinge on V8 XJ Series. Be sure to apply the clear protective sheet over the label.

 

Here's TSB 303-49:

303-49 Restricted Performance.pdf

As Steve says, if it has been reflashed, there should be a confirmation label attached.



Graham

 

Thanks DaveC, that makes sense with staying in 4th for manual shifting. The owner said he thought it was supposed to spring back to Drive since that is the behavior that he saw since he’s owned it for the past 8 years. It leads me to believe TSB 303-49 has a good chance of addressing the issue, I’ll elaborate in a bit.

And thanks steveinfrance, I did find that J-Gate thread in my searches before posting this thread. Almost the issue I see, but mine is not intermittent, mine is very predictable, and I don’t see the issues with the indicator lights, gears not changing, or the sport mode switch not working. All of that seems to behave properly. But if the ECM update doesn’t work, I’m definitely looking at the sliders and switches in the shifter console next.

And thanks steveinfrance and GGG for the info on TSB 303-49. I did not find the confirmation label. I also called the Jag dealer where I know the vehicle has had service, and many TSB’s were listed, but TSB 303-49 was not listed as being done. The TSB information is very general though, it doesn’t mention exactly what the calibration is which would tell us for sure, but there is the connection between the Engine Control Module (ECM) and Transmission Control Module (TCM) in the TSB. I asked the service manager about more details, and he said that he believed it has something to do with the calibration of the sensor or slider locations and which gear the ECM thought it was supposed to be in. Other than that, he said he knows as much as we do from the limited details in the TSB.

But that makes sense, the shifter may be wanting to spring back to D from 4th because the ECM mistakenly thinks it is supposed to be in location D. When I occasionally get it to stay in 4th, which feels more like it got stuck in 4th (perhaps because of physical sensor slider tolerances) rather than wanting to be there, then the Restricted Performance trips.

There may not be many cases of this issue yet because the TSB has a limited VIN range “A00083 – A22973” and “F00103 – F40247” from 2000-2002. Plus, those in this range would have to at least occasionally use manual shifting to see the issue. My friend only occasionally downshifted to 4th from Drive when passing at highway speeds. He believed the spring back to D was on purpose to provide a speed shift feature quickly back to Drive. He didn’t downshift to 3rd or 2nd much, which is when 4th occasionally gets stuck, coming back from 3rd. This issue may also exist for others that just don’t manual shift at all.

The evidence seems to point to TSB 303-49. That will be my next step, and I will post the results.

Thanks again everyone!

 

Seems logical but the bias to D is mechanical and not right - there's no feedback from the ECU and that makes me suspect the shifter mechanism.

 

Do you happen to know what triggers the TSB is supposed to address ... other than the message showing up of course. The TSB only mentions the presence of the RP and LH messages.

 

.......... just that the threshold values triggering Limp Home Mode were too low.

Whilst many actions covered by TSB's are only carried out following customer complaint, this reflash seemed to be done automatically by UK Dealers at service so few owners were troubled.

Graham

 

Ok then.

In any case, the posted TSB is a also a good step-by-step tutorial on how reflashing is done.

edit: thresholds on what parameters?

 

My dealer contact tells me it was TPS and PPS. No more detail available as that many years ago, it's history to them now.

Graham

 

Based on the latest posts, I am not as confident that the ECM update will address the issue. New calibrations for throttle and pedal position sensors don’t seem to relate to my issue. But I should still get it done from what I surmise.

I finally spoke with a transmission place that has worked on Jags, and he said it sounded like a shifter cable tension issue, possible adjustment or cable replacement. I will search the forum for J-Gate cable adjustment threads and see how complicated that is.

 

It's not that bad. Fiddly, but not bad.

You may find in your case, that there is also a outright mechanical defect in the shifter because of the 4-D problem.