Hello and Happy Thanksgiving to all.
I posted this last night to General Information forum but I realize it should have been here in X100. I hope I'm not violating any rules by doing so.
I operate a small independent Jaguar repair shop in upstate New York.
I recently replaced the J-gate module (part # LJA6195BG) on a 99 XK8 due to a crack in the plastic--strictly cosmetic. On the original one, all of the gear position lights lit up as they should when the gears were selected.
The new assembly came from my local Jaguar dealer. Once installed, I realized that only P and N illuminate as the gears are selected, not R, D, 4, 3, 2. I contacted the dealer and they sent me another one. (new, sealed box).
The second new one behaves the same as the first: Only P and N light up (when selected); the others do not.
When I reinstall the ORIGINAL (cracked) module, all of the position indicators illuminate as the gears are selected.
Has anyone replaced a J-gate module in one of these? If so, was it plug and play or was it necessary to program/configure/code the new one?
Jaguar says check wiring (loose or pinched wires) or a CAN problem. I have IDS but I see no option for coding or configuring this module.
Dealer was good about getting me a second one but I'm reluctant to ask for another unless I am confident that it is a bad batch(?).
I mean, what are the chances of getting two bad ones, both behaving the same? I know, probably low but greater than zero.
I believe the rotary switch on the gearbox reads the gear position and energizes the various indicator lights via the 9 wire harness on the J-gate.
Correct me if I'm wrong about this.
Any help greatly appreciated.
Thank you.

Patrick
The Gas Menagerie
Troy, NY

 

There are good knowledgeable folks on this board regarding this issue (i.e. not me!) but I seem to recall that there are subtle adjustments to make when these components are replaced. It has to do with making sure all those micro switches are activated when required. Remember, these switches inform the trans control module of the stick position. The module then sends CAN messages to the illumination module for the lights. This illumination module is a write-only CAN device. It does not know or care of the stick position. At least that is my understanding. Hopefully someone else can help out with more details.

Best of luck, keep us posted.

 

I just checked my photos of when I replaced a bulb in the j gate (1998). There are 2 bulbs on the circuit board inside the j gate assembly. Both are always lit with ignition.

The j gate is a circular plastic plate which rotates according to shifter shafts position. There is a little window on the circle that moves as the shifter moves. Light fro. The bulb illuminates gear selected through this window.

Like I said this is on a 98.

If it were easy wiring I'd say check for bulb voltage. The connector passes sport switch and cruise switch signals too so it's not easy to say where to probe.

John

 

Thanks fmertz (how's Ethel?) and Johnken.
At least on the 99 XK8, there appear to be separate bulbs (or LEDs) for each gear position on the J-gate. I've gone so far as to plug the 9 wire (10 cavity) harness plug into the OLD J-gate with the NEW J-gate installed on the car. As I move the shift lever through the gears, each light illuminates in red on the old J-gate, as it should.
However, with the NEW J-gate plugged in, only P and N light up in red.
It seems to me that this would indicate a problem with the new J-gate. This is the second new J-gate from the same dealer (both ordered in/not "on the shelf") and they both behave the same.
I am convinced that the parts are defective but must rule out any other possibilities before asking dealer for a third!
I'm still hoping to hear from someone who has replaced a J-gate and has NOT encountered this weird result.
I DO appreciate both of your replies and recommendations.
I'll keep you all posted.
Thanks again.

Patrick

 

Wrong part for the year of car? Did they order my build date or by VIN?

 

Not wanting to contradict anything previously posted but - two of the three microswitches are on a separate metal bracket and not part of the J Gate assembly.


I am pretty sure that the "backlighting" is from the two small incandescent bulbs, but the "shift position" lights are LEDs built into the PCB.



I had a similar issue - new J Gate Module and position lights didn't work. S N G Barratt were great and did a full refund/return and referred the matter back to Jaguar. I never got a totally satisfactory reply, but I suspect that there may be some subtle software differences which can affect the way this small module functions.

Depending on what customer wants and can afford, I would EITHER replace just the top cosmetic cover from new to old (expensive but effective) or get a good condition cover (or complete J Gate assembly) from a breakers (parter-outer ??)

 

David, I bet you are right. I was trying to look at a photo on my phone. I too have leds, what else were they for? For the record i withdraw my description. Thanks for catching that.

Now let's recover ��. You have access to both jgates. If the chip driving the which led to light is not on the j gate, check continuity between the trace to one of the less in question from the pin on the wire harnesses connector. Heck while you are in there set your meter to diode and make sure the new jgates LEDs are not open.

I hope it is straight wire to the less for you. That'll make it easy to trace differences between the two. If you're not good with this tug, though you sound like you are, just ask about continuity or diode testing. Good luck and let us know how you do.

John

 

From DevonDavid's earlier message: "I had a similar issue - new J Gate Module and position lights didn't work. S N G Barratt were great and did a full refund/return and referred the matter back to Jaguar. I never got a totally satisfactory reply, but I suspect that there may be some subtle software differences which can affect the way this small module functions." I believe this is a situation identical to mine. This is what I have been looking for. Someone who has had a similar experience with J-gate replacement. So the next question is: Should a component supplied by Jaguar work in a Jaguar (with or without a software update)? I'll try to get that elusive "totally satisfactory reply" and confirm "that there may be some subtle software differences which can affect the way this small module functions". Stay tuned. And thanks to all. Patrick

 

Can a moderator try to combine the 2 threads??

Stupidly I posted in the General forum post.

bob

 

You should return the module and purchase just the top cover off of eBay. I just bought one - now all I have to do is figure out how to install it (photo shown is for my '05).

 

Just the covers are hard to find. If there is an eBay source, buy them out. The 6 speeds are even harder to find.

Install is a straight forward but a PITA. You need to pull the entire module (disconnect from car completely) and then you can unassembled and replace. Depending on how your wires are run, you may need to pull the center console but if you are lucky you can unconnected the module (the connector does not disconnect at the module side, instead it has a soldered 6" or so lead thats wound to its left).

 

Thanks. Somehow I thought 'GGG' once said it was an easier chore on the newer models(?). Perhaps not.

Here's one on eBay (5 spd version). Get it while you can!

 

PatrickO, the part # you listed is used to replace the following part #'s

LJA6195BF, LJA6195BB, LJA6195BE, LJA6195BD

In the Bay listing I found for your part# the seller made the following statement...

"This item may have been superseded from a different part number from this manufacture. This is only provided for reference, the part being sold is not guaranteed to be equivalent to any of the part numbers below."

What was the part # of the one you replaced

 

Hello RDMinor, The J-gate module I replaced was a LJA6195BF. LJA6195BG is correct for VIN according to the dealer I purchased it from as well as jaguarclassicparts.com.

I'm still waiting to hear from Jaguar (via dealer) and Jaguar Classic Parts (via their Parts /Technical Advice enquiry option). I asked both if they could explain why the replacement parts don't function fully. It has been a few days, no response so far other than a vague reference by a parts counterman at dealer to "some problems" they are having.

I did receive a reply from SNG Barratt confirming a similar situation experienced by DevonDavid, recounted earlier in this thread. Unfortunately, all they said was that the part was returned to Jaguar and no further information was provided. At least they responded.

Thanks for your time and interest.

Patrick

 

BF[QUOTE=PatrickO;1802243]Hello RDMinor, The J-gate module I replaced was a LJA6195BF. LJA6195BG is correct for VIN according to the dealer I purchased it from as well as jaguarclassicparts.com.

Patrick[/QUOTE





BG might well be the only currently available NEW part but it obviously isn't the same for whatever reason. The listing I found on eBay for BG that the seller was very clear about it's possibly not being totally compatible is probably evidence that they'd experienced some compatibility problems before.

On a lark I Goggled LJA6195BF and found these:
1997-2002 Jaguar XK8 Floor Shifter Gear Selector Indicator Module LJA6195BF: Jaguar Used Parts, Auto Body Supplies, Salvage Car Wrecking Junk Yard

1998-2003 Jaguar XJ8 Floor Shifter Gear Selector Indicator Module LJA6195BF LNA5850AA MJA4913AB: Jaguar Used Parts, Auto Body Supplies, Salvage Car Wrecking Junk Yard (This has several other parts attached so there are 3 #'s)


https://www.motorcars-salvage.com/GE...LJA6195BF.html

There were others but Russia, Australia, and the U.K may be a stretch for a used part<G>

 

At this point, I think it is fair to say that there is a problem with the LJA6195BG being offered as a replacement for the LJA6195BF, at least for use in the XK8.

So far I have been unable to determine what that problem is and what remedy there may be. It may require a software update easily performed at an authorized dealer although I would have thought this would have been expressed to the purchaser (in this case, me) when the part was ordered.

I still may hear from Jaguar, via dealer parts department or Jaguar Classic Parts, with more details. If and when I do, I will share that information on this thread .

I will probably return the car to my customer this week, with the ~$400 part installed, and suggest that he bring the car to the dealer from which the part came. Presumably it can be made to function properly there.

I will let you all know how it plays out.

Thanks to EVERYONE who contributed. I do appreciate all the help.

Patrick

 

Customer took this car to the dealer (same dealer the two new parts came from) and after some "testing" they ordered and installed a third new one and it worked properly when installed. Parts man told me the tech disassembled the previous, non-functioning unit and remarked on some "shoddy looking" solder connections. Looks like Jaguar had a bad batch. If you find yourself replacing one of these, be prepared to install a few before you get a good one. It may be that the returned ones are going back on the shelf.
Hope this helps someone.
Thanks again.

 

Fascinatingly enough, I just ordered LNC6195AC for my 2001 XK8, mainly to replace the gasket which was disintegrating and that I have been unable to find without the module. The module was apparently new in box, installed it, it had a newer version of the illumination module board (B30625-01), but same behavior as noted here. P and N illuminated, but not R, 4, 3, 2. Reinstalled the original board (had previously repaired the incandescent lights and resoldered all of the off-board connections), they work fine.

However, it does indicate a 'production date' in 2018. Wonder if this is from the batch discussed in this thread, or is one of the actual 'bad' boards discussed in this thread.

 

Following up, the vendor sent the following

"I am sorry to hear of your issue with the J'Gate you purchased recently. Please see the below comment from the manufacturer, explaining the issue:

A little history / background for your information; ANM reverse engineered the unit in 2010 and found that circa 10% of the vehicles on the road have not had the various software upgrades at routine servicing (to the gearbox and TCM units (transmission control modules)). It was decided by JLR at the time, that rather than
run the risk of introducing “other issues” on changing the J Gate, we would ReMan the small percentage, as the last thing we wanted was to upgrade an older
vehicle with new gearbox and TCM code to find the vehicle would not run properly afterwards, (given that we would not know if any “third parties” had interfered
historically with the software/hardware for example mapping systems etc).

This being the case, as there is no way to re-engineer the new 'J' Gates to match the unknown mapping of your transmission, we will need to arrange collection of
the new unit from you and give you a refund in full."

This is another fascinating aspect since, 1) the original board works correctly, 2) it appears from the wiring diagram that the red leds are addressed using the CAN bus. So, it's hard to imagine that this explanation makes particular sense (i.e. the CAN bus codes/mapping have changed? with a new gearbox?, transmission module?, software upgrade?). There appears to be no programmable part here in any case.

 

Fascinating. Maybe the original board was really a ZF part, and always responded to several sets of commands (BMW, Jaguar, etc.) with the same result. Then maybe Jaguar at some point switched from one command set to another as part of a ZF software update. Now, when the part was reverse engineered at a later point, only just the later set of commands was identified. It means the new part only worked with the corresponding software update installed. As the note says, for cars running the older software, the path forward involved re-manufacturing the original part, i.e. there is no new part available.

So, in theory, if you were willing to assume the risk of updating your TCM to the latest code (reflash), this new part would then likely work.

Just my thoughts.