2003 XKR Coupe - ZF 6HP26 six-speed transmission.
89,000 miles, Fluid and filter change done at 80K - with ZF "Lifeguard" fluid.

Those that have read my other posts know how much "love" I hold for the 6HP26 transmission and the (non)control of it that Jaguar let's us have. But, that aside, I have a recurring problem that sounds like something I "should" be able to fix - with a bit of guidance from other forum members.

I drive in "sport" mode and shift through all gears manually 98% of the time - Partially because I want to make the decision of when my car goes into the next gear and also to reduce the effect of the "surge surge surge" cold part-throttle annoyance that the '03 and '04 ZF trans is known for.

Problem: When I have been driving for 15-20 minutes (particularly when I'm on the highway and usually in "drive" or 6th gear) often, but not always, the gear selection indicator light on the J-Gate console starts flashing. The manual shift option (2nd,3rd,4th,5th) of the J-Gate becomes inaccessible, the light on the sports switch turns off and "sport" mode can no longer be selected, basically leaving me with just automatic "D" mode. The auto gear changing goes very sluggish when this occurs. When I get to my destination, the "P" or park indicator is also flashing. The system will eventually reset itself, but takes several stop and restarts of the engine before it will go back to normal (the pattern of which is not predictable.)

Sometimes i can drive 20-30 miles distance before the indicator starts to flash, sometimes just moving out of Park to Neutral or Drive when cold is enough to cause it. The flashing "D" light and sport mode lock out is liable to happen when the shifter is any and all shift lever positions and when it does, the system always defaults to "D" or Drive. There are no warning lamps lit on the dash info center. Obviously it's going into a limp-mode of sorts, but what's causing this?

With extensive Google searching, I have found a few references to this problem happening to a few other XKR owners and that the problem may lay within the "linear switch" under the J-Gate Shifter. Hmmmmm?

Has anybody else out there had this problem and know conclusively what will or HAS solved this annoyance?

If the problem is in the linear switch, can I take the thing apart and clean it? With any sort of assurance that doing so will fix the problem?

NOTE: the former owner of my car was a regular coffee w/cream&sugar drinker and driver - and damn near every one of the console/radio switches have had to be cleaned of sticky, sugary goo!

Also, I have seen a JTIS .pdf on removing and replacing the linear switch - but I think I may have been looking at information for an earlier model. Is the 2003 linear switch the same as an '02 and before?

After removal is the re-installation and the adjustment of the linear switch a difficult process?

Guidance needed!

Thanks Guys,

 

The flashing lights on the shifter indicate a tranny controller problem.You will need to go get the codes read. If this is a problem, trace the wires for the harness and make sure all the connections are clean. Spray them all with electronics cleaner. If the flashing continues get the codes read, the controller is to expensive to guess at.

 

By the way, the controller is inside the tranny, just clean the connector plug on the tranny.

 

This is good info but does not mention the flashing lights that I can find.

http://www.europeantransmissions.com.../6hp_trans.pdf

 

I had this symptom and doing research also found the problem to be with a control assembly, which is part of the J-gate assembly, called either the Linear Switch or Transmission Control Switch (Varies with different versions of JTIS).
My problem eventually became permanent!

Replacing this cured my problem and all has been OK for the past 10 months.

The part number of the switch I fitted was C2N 2467, I dismantled the old one and as far as I could tell there wasn't any adjustment or cleaning that would cure the problem. I think it was electronic failure

It was easy to replace, all done from inside the car, just one electrical connector and the alignment using JTIS is very simple.

The manual gear change selection, left side of the J-gate, is all done electronically with the 6HP26 gearbox, fitted to the 4.2 versions.
See J-Gate description attached and JTIS Linear switch alignment instructions:

 

Thank you guys! I checked the DTC codes and have nothing, but if those are codes that are logged in the transmission control module (if that module even stores codes) - I may not be able to read those codes with my OBDII reader.

Stumpy: I did further digging and saw an incomplete thread here at JF about a resistor in the linear switch having a bad solder joint.

I'll call tomorrow and check out how much $$$ Jaguar wants for that C2N 2467 part number too.

Oldmots: thanks for the 30 page OBD manual on the ZF tranny - I've got some bedtime reading... Yea! Reading that will probably answer my question about code reading.

By the way, do I have to take the console completely OUT of the car to access that linear switch? Or can I do it from the top.... It's been a year since I was inside the console cleaning sugar goo out of switches and honestly, I wasn't looking for that linear switch - so I have no memory of seeing it.

 

+1 for cleaning connectors.

To your question about the codes, you are correct, you cannot read them with a standard OBD reader, you will need something that speaks native Jaguar, like WDS or AutoEnginuity.

JTIS says that you remove the console, the selector lever and then the transmission control switch. The switch is on the side, so I'm going to say that you probably do have to take the console out to get to it, but you could pull the wood surround out and see if there is enough room to work.

I had a similar "looking" thing happen one time while I was reading codes and the dongle blew up. This thew the CAN communication into a tizzy and caused all sorts of strange messages, including the flashing gear indication like you describe.

The linear switch and indicator are CAN modules and if they loose communication with the rest of the transmission it will go into a failsafe mode, which is what it sounds like yours is doing.

Since sport mode also goes away, it's most likely the linear switch as the sport switch is only connected to that module.

 

I checked all my joints with a strong magnifying glass and found no problem. You may be luckier.

I have attached the exploded view of the J-Gate assembly. The switch is #27, mounted on the RH side of the J-Gate unit. The surround only appears to show 3 gears on the LH side but the diagram is correct.

If it turns out to be the Linear Switch you will need to remove the J-Gate wood surround and the centre tunnel assembly. As the J-Gate assembly will need to be unbolted from the chassis/tunnel to remove/install the switch!
Also attached centre tunnel removal instructions, to refresh your mind.

 

Thanks again for the continued assist for the impending surgery on my XK!

Stumpy, thanks for the article on console removal.

Over the Thanksgiving weekend I plan to jump into this project. I called the local Jaguar dealer here in Kansas City and the part runs $307.39.

I suppose that's not TOO bad for a very "application specific" Jag electrical part - but considering the cost, I may do myself the favor of attempting to disassemble the part and examine it closely for any signs that I may be able to "clean" it or re-solder any parts that look suspect, before I "blow-high dough" on a new OEM part.

I'll keep ya'all informed on what I run into!

 

I have attached 2 pictures of the Linear Switch internals, a Torx T8 screwdriver is needed to dismantle.

The PCB photo shows the P-R-N-D slider track at the top and the 5-4-3-2 track at the bottom.

The slider/case half photo shows the P-R-N-D slider contacts at the bottom and 5-4-3-2 slider at the top.

There is also a similar thread running here:
https://www.jaguarforums.com/forum/x...69/#post624973

 

I have the same problem

 

Had the exact same problem first cleaned the contacts to the transmission which seemed to help a bit then replaced the linier switch and haven't had the problem since.

 

Hello,

Somebody finaly found the problem ?
Stumpy, what did you do to solved your issue ? (or, it seems you change the linear switch)

I have the sam issue on my car (XKR 6 speed, of 2003). I will unmount the switch, and try to use contact spray to see if it solved temporary the issue. i let you know.

Regards,

 

finally, I disassemble the switch, and I sprayed a spray for electronic circuits all overs the electronic part. I also used the spray on the connector of the switch (the switch connector and the other part, wired in the car). And I clean with acetone the electronic tracks. I twisted a little the two combs for better contact. And it imediatly work !!

I let you informe if it still works in one month.

To remove the switch, you need to unbolt a little the entier J-Gate module (without removing it).

 

2003 XKR I had the same problem with the transmission position indicator lights flashing and no sport mode. This would come and go and was getting worse. I replaced the lineal switch myself and the problem is resolved. The part cost less than $300 and the task took about two hours.

 

I just "fixed" mine.
Same problem as everyone else so, after seeing this thread and watching Rev. Sam's video, I went out and proceeded to remove the console. During the process, since I needed to move the shifter to clear the console parts, I noticed it quit blinking! Gee, all my gears are back! I went ahead and loosened and retightened all the bolts and connectors before putting everything back together. Here's hoping!

 

I followed your advice and changed the Linear switch, everything seemed fine, sport mode was working, then it stopped working and I have no second gear. Is there an adjustment I need to make? How do I make it?


thanks
Perry

 

Perry, welcome to the forum.

What year are we talking about here?

On the 2003+ (6spd) it is all electronic, so no adjustment to make really. Dirty contacts are the usual culprit.

Earlier years are done a little differently, but if #2 is the ONLY one that doesn't work, then it could also be dirty electrical contacts.

 

Charlie it is a 2004 xk8 convertible. as with most of the members on this thread the blinking D was the start of everything. When I researched everything it seamed a challenge but not too complicated. I found I had to disconnect the shifter cable as the switch would not come out and in doing so I may not have got it back exactly in the same spot. BTW my check engine light is now on as well. As I have no manual I seem to be a little stuck.

 

Do you have a code reader to get the check engine code?

Is it only second gear that doesn't work? Or are all of the manual gears inoperable?

If it s all the gears, do you get a flashing P when switching the car on?