Hey Lads,

Found several posts on the topic but none of them followed up with a resolution, so I decided to start my own thread to follow-through with the problem and hopefully the fix.

Regular user of the J-Gate and sport mode on my 2003 with the ZF 6-speed autobox.
First thing I noticed was the car not responding to manual downshifts. When I looked down, I could also see that the sport mode button, although engaged, did not show its red light. Scrolling through the gears made no difference and car moved along in normal auto mode without issues. No dash warnings, no flashing of any lights on the shifter. Just a blank sport mode button and a permanently engaged auto box. Shutting the car off and returning later results in both being back in business and this loss of J-gate and sport mode seems to happen only while I am driving the car for a while. What I mean is that it has never revealed itself immediately from when I start the car.
Have seen a variety of suggestions to others who have experienced the same issue but have not read where someone has cracked the issue and posted the result.

So - lets have at it!

 

I'd say check the j-gate lights as you move the shifter. These lights are not directly driven by the underlying switches. They reflect the opinion of the TCM as to where the shifter is. That opinion is itself driven by the actual state of the switches. You should then be able to determine if one of the switches failed.

If you have a JLR code reader, there should be a way to read the state of these shifter switches as you move the shifter around.

For the sport mode switch, it has been known to stick and sometimes fail. Best is to start with some form of evaporating spray to clean it up. Fortunately, the j-gate trim on our cars is much easier to remove than on the earlier models.

Best of luck, keep us posted.

 

I will get to digging into it here soon.
I have the JLR software, but I don't know if that is going to get me into the codes for this particular issue? Will hookup and find out, I guess.
What I can say with 100% certainty is that with my car, the loss of J-Gate and the Sport-Mode happen together each time. It's happened enough times now that I know the symptoms.
And, if I shut the car off and wait a few minutes, it all comes back on startup. Almost seems like it is getting locked out for some reason by the TCM. Once those features stop working while driving, they do not come back until the car has been turned off for a spell.

Thanks for the suggestions and I will look into it

 

Interesting info about what drives the J Gate lights. Regardless of red light on S button, Is there an easy way to tell if S mode is actually engaged?

 

Too me, the whole set up seems a bit over complicated as designed but I'm sure there are reasons (beyond my understanding) for the level of complexity when it comes to the stick and all the interdependence - what lies beneath

Seems (I thought) SM, manual JGate and auto function work independently of one another. That SM can be on or off, and one can use the manual and auto function regardless...? Strange.

Maybe sport being disabled is simply a symptom of that option being "shut down" when irregularities are sensed?

My first thought was the linear switch (03 has this right?). Dirty, warn contacts, high resistance, malfunction with its operation due to cable/trans arm positioning...?

What about leaks at the seal on the trans connector plug? Or an accumulation of things?

​​​​​Does the car "wait" for you to start using the jgate and the SM to get nasty with ya and shut everything down?

Do any of the selected gears ever blink and not work?

Just throwing things out there

 

Ordinarily that is the case.
I can have SM on or off and still switch between auto and J-gate.
However, when this absence of J-gate occurs, sport mode LED on switch always turns off at the same time - so there is something, somewhere, that cross connects with both features.
Whether that is in the hardware or in the TCM is still unknown to me at this juncture.
I have never seen any flashing lights on the shifter but what I can add is that when this occurs, the shifter light stays in D regardless of where I put the shifter in J-gate.

I completely went through my entire transmission a couple of years ago and it was an elongated troubleshooting process to say the least. I was successful in tracking down my issues but while I was on that journey, everything got a refresh on the serviceable components with the transmission in the car. This included all seals and even a valve body rebuild which worked wonders on the smoothness of the shifting BTW.

If it was something that stayed broken, it would be much easier to isolate but again, if I shut the car off and then restart it, the issue stops for a while. This leads me to believe that something in the TCM is stopping J-Gate and the SM due to some data it receives and doesn't like but without any data being splashed up on the dash, it is going to require a deeper dive in isolating the problem. I am hopeful that when I get JLR hooked up, it might reveal something buried in the trouble codes. Fingers crossed.

 

The light is a clue there is likely something wrong with either the "D" or "5" switch. Either the "D" switch stays "on" as you land on "5", and the transmission thinks you are on "D" and "5" at the same time, or "5" never clicks on, so the transmission see you leave "D" but never land on "5". To my knowledge, these switches are pretty common to procure and generally fail on a "sometimes" basis (see the many brake switches threads).

It is very likely there are codes the TCM generates once it sees inconsistencies in the shifter switches. You can put those into a search in the off chance this has been addressed before.

Best of luck, keep us posted.

 

Totally makes sense.
Will start my search on the switches down there and see if I discover anything wonky. Will also see what has popped up in JLR if anything.

 

For me S mode check: level road 33mph, floor it. Huge difference S on vs. S off.

John

 

Thinking about a "switch"....from D to 5 at the bottom of the shift assembly...

Unless there is a difference between the 2003 and 2004. Mine is a 2004... On mine, when you get the shifter down to the bottom of the shift assembly there is an upper post on the stick that fits into, is inserted into, a U shaped groove on the UPPER RH side of the shifter assembly. When the shifter is on the RH side this upper post is always in this U shaped catch/bracket. The U shaped catch drags the cable forward and back from P thru to D at the very bottom RH counter of the assembly...

Once at the bottom (direction of the rear of the car) of the shifter assembly in D,,, and the "shift" is made in stick from the bottom RH side to the LH side of the shifter assembly, there is a 2nd LOWER post on the stick that fits into a second lower U shaped catch/bracket (upside down U, I think) which is also on the RH side of the guts of the assembly...

The second and lower U catch/bracket in the shift assembly is stepped towards the front of the car, which allows 5 and forward shifting thru 4, 3 and 2 to CONTINUE moving the shift cable in the rearwards direction. So, cable is still moving towards the rear of the car attached at/on the RH side of the shift assembly even thought the shifter is moving forward (towards the front of the car) on the LH side due to lower post on stick engaging/meshing the lower U shaped catch/bracket on the RH side of the assembly internals...? Is that an accurate attempt at explaining that, lol???? Lol, I got carried away hahaha

Anywho,,,

Where, and is there, an actual D to 5 mechanical switch in there somewhere OR is all of that seansed electronically in the linear selector switch on the side of the assembly?

Wait, is the micro switch attached to that big ol CIRCULAR disc shaped thingy that must swing around when you move the shifter at the bottom from RH to LH sides? Or is the switch on the walls of the assembly somewhere and is engaged when the disc swings around?

Oh shoot. I think I just learned something, 🤣

 

I have had my 2005 since 2008 and had something similar happen only ONCE for no obvious reason. That is I drove the car somewhere and it was fine, turned off the car for a short while, came back a bit and started the car and wasn't really paying attention to the status of the sportmode light, drove a while and then hit a downhill area and wanted to shift to a lower gear, noticed the shifter had no effect (didn't downshift) and then is when I noticed sportmode light was off. I returned home and the car drove fine (except for ability to manually shift), parked the car, went on the pc to post the issue to this forum and learned all about linear switch, etc. So was all ready to bring to the local mechanic but upon starting the car everything was back to normal--sportmode light on and ability to manually shift.

With this car, over the years I have noticed a number of random but infrequent weird happenings and virtually every time "things" happen they seem to disappear after turning off the car and restarting.

Doug

 

As mentioned before, your problem most likely lies in the linear switch module (J gate), the sport mode button is a subset of that. All J gear changes are CANBUS commands sent from the linear switch module to the transmission. All the Sport button does is tell the linear module to send the sport version of the command rather than the normal version.

If there is a communication fault and the linear module is still powered you should see a flashing D. If you have a more fundamental problem like power interruption then the linear module will have no lights.

If it works sometimes then my bet would be a dirty connection or a questionable wire in the harness that goes to the linear switch module. It is located immediately under the wood shift surround.

I would try an experiment: You say it works when you first start the car so try toggling sport on and off right after start up. I bet it works as normal.

Now try moving it through the J and see when / if the lights go out or if D stays illuminated or flashes when you move over to 5.

Lastly, try knocking on the linear module like you are wanting to see if anyone is home. I bet you can make the fault happen by introducing some vibration.