My 2004 XK8 J-shifter quit working on the left side tonight. I was able to down shift on the left side earlier today. I also noted that the Sport mode button does not light when depressed. It seems like an electrical problem.. connection, fuse? Any suggestions before I go to the shop? Thanks!

 

I use the left side a lot and had an intermittent issue for two years before I got it to a good mechanic that figured it out.

First things first:any error messages on the dash? If yes use a code reader to see the faults.

If not check to see if the gear selector illumination (the D/N/R) light is flashing once you put it in drive. More than likely it will be operating fine today, but when it fails again look for that. If it is flashing it is probably the linear switch which is an assembly below the J-gate module that is the electro mechanical switch for the transmission. However we also replaced the J-gate module itself and adjusted the linkage before we ID'd the linear switch as the issue. Have you ever spilled or dropped anything into the J-gate? This may be the cause.

If it is not flashing then it could be two other possibilities: I have seen this happen when there is low battery voltage or, on rare occasions, I shifted too late and it appeared to go into a protection mode (no codes or warnings) and just seems to go back to drive no matter where the lever is on the left side, the sport mode button will also no longer be illuminated no matter what position it is in. This is resolved by restarting the car. You can also check all the electrical connectors on the drivers side (LHD) of the trans tunnel in the center console around the J-gate. Lastly it could be the switch, but if you start it up today and it works it is probably not the switch.

Lastly, I mentioned my problem was intermittent I believe this is because I used electrical contact cleaner on the Sport mode switch and down in the J-gate which I believe helped prolong the life of the linear switch. By the way I never received a code once about the failure.

 

Marc, THANKS! All good scoop! The linear switch was replaced a couple of years ago when it went out ... I had the flashing "D" back then. Not this time ... and it all worked well today. I'm a careful shifter when I use the left side ... gradually down-shifting ... staying in range. The spilling on the console is the more likely culprit. I guess I'll have to keep a rag there, too. I always keep a rainy day rag in my lap for getting in and out of the rain ... convertible drip! So, I'll be keeping an eye out and for future events. Thanks, again!

 

are you getting the trans over temp warning at the same time? If so it could be the trans subharness, I hsve that issue with mine and that is where I am going with it if it gets worse.

 

The J-shifter/sport mode intermiitent is my only problem now. I just had the right side HID replaced and the coolant level sensor replaced (under my extended warranty ... thankfully!) While I was in the shop, I asked them to check for "codes" on the shifter, but nothing showed up, and, of course, the "bugger" was working fine while it was with them!