Good day All,

I had to replace a J-Gate/Linear Switch, also had to fix the Gear Control Cable. Now, the car no longer starts after the J-Gate replacement. It is definitely related to the J-Gate assembly, as I've tried reconnecting the old one, and it starts just fine.

The new replacement J-Gate assembly, has what appears to be an extra connector, bright yellow in color. My original J-Gate did not have this connector at all in any color. I see no place to connect it either. With the new J-Gate installed and connected, I can crank the car, but that's all it does is crank, never fires. As a test, I connected the old J-Gate back up (with the new one still installed) and the car started perfectly fine. I then disconnected the old J-Gate and reconnected the new one, and it continued to run perfectly fine. Yes, of course all the error lights possible came on for a brief time until the new J-Gate was fully connected (except for that one connector where I have nowhere to plug it in), then the error light went off, except for the ones that were pre-existing (Transmission Error, Restricted Performance, and CEL is on). I suppose I need to connect a scanner to clear those codes and see what I currently have.

At any rate, using the old J-Gate to start the car and then reconnecting the new one, the car shifted into gear perfectly fine, moved perfectly fine (as expected in Restricted Performance). But once I powered it off, and went to restart it, same issue. It cranks but doesn't fire.

I'm guessing I may be running into some security issue perhaps? Some sort of fail-safe? There's obviously SOME reason the Jag likes the old J-Gate and has issues with the new one. I ordered it from Coventry West as a direct replacement for my year/make/model (01, XJR).

I've seen on here that sometimes the Jag thinks a new replacement part is "foreign" and bitches about it, but not sure if that's what is going on or not. And if it is, any ideas on how to clear the codes? Is it possible to clear them without a scanner, or to reset the computer (if that will help with this issue). OR, does anyone have any ideas what the extra connector on the new J-Gate is/is for? I feel that I'm much closer to getting this big beautiful cat purring again, but running into issues at the end lol.

Thank you much in advance.

 

Sorry, I have been busy.

I am by any mean a Jaguar mechanic, so please wAIT for other members assistance.

Shifter solenoid is the metal cylinder shape piece attached on the opposite side on the assembly from the linear switch.

You can Google for the pictures.

I also these parts for sale if you need

 

Thank you, yes, the assembly I purchased does come complete with all pieces. Just very strange with the "extra cable". The original doesn't have it, and nowhere to plug in (that I can see), unsure if that's causing it not to fire, or some other reason. All I definitely know at this time is that it seems to be related to either the new J-Gate itself, or the car's "acceptance" for lack of a better way to put it of the new J-Gate. As it cranks and fires normally with the original. Very very strange. I've never run into this issue on other cars.

 

Try to check microswitch on the J-gate what indicates that the shifter is in P position. If it doesn't work properly car is thinking shifter is not in the right position.

 

Rostman,
I thought that the naturally aspirated models used 2 microswitches while the supercharged used a linear switch. I spoke to the company I bought it from today (Will leave company name blank for now). They said that someone there had attached a piece for the XJ8 naturally aspirated model to my shifter prior to shipping it by accident. This is supposedly the reason for the bright yellow "extra" connector. I was directed to remove that extra connector (a single red microswitch at the front of the J-Gate), which I did. After removing said microswitch and connector, I now get the expected beeping sound if I try to move the shifter without depressing the brake, prior to removing this microswitch I wasn't even getting the beeping. However, the car still cranks, but doesn't fire.

I told the company I purchased it from the results and they said "Hmmm....that's weird, let me call some of our customers who do this all the time and see what they have to say and get back to you..." So....that being said, I figured I'd ask you fine people here. I admit to being stumped. I'm grasping at straws.
I was wondering, is the J-Gate the exact same for both XJR and XKR? I've seen pics online of what is supposedly an XKR and it appears to have the bright yellow "extra" connector on the right side. I was wondering if I may have received a part for XK as opposed to XJ. I know the part differs for supercharged vs. natural aspirated, but unsure about XJR and XKR. If anyone has any thoughts or theories even, that'd be great! Thank you all in advance.

 

I'm gonna throw out one idea I had. I wonder what the "illumination module" looks like. What's an illumination module? The part of the shifter that the gear change sticks through and displays the actual gear. This piece is specific for supercharged or naturally aspirated. Look at the new one versus the old one. The old one, if I remember correctly, on the supercharged cars has a very long left side of the shifter. It nearly goes up to the star screw for the emergency release. The N/A cars have a shorter left side.

The illumination module is part of the CAN network that allows powertrain functions to occur. It does nothing more than display (illuminate) which gear the transmission is in based on signals passing along the CAN network. The wrong illumination module will cause a no-start. It is not a module that needs programming as it does no actual work. It is considered a pass-through module.

Hope this helps.

 

BlackX300VDP,

Thank you very much for the response. I looked at the illumination module on both J-Gates. It appears to be the same on both. If it would help, I can supply pictures. Thank you for the information, I wasn't aware of that bit of information. I'm realizing that there are quite a lot of differences within the same model year, especially between Supercharged and Naturally Aspirated.

 

UPDATE:

Spoke to the company I purchased the replacement unit from again. They suspected it may be a fault in the new Linear Switch causing the issue. They suggested trying to use my old Linear Switch with the new J-Gate. Once I did this, the car started right up! So, apparently that was the issue. They're sending me out a replacement Linear Switch. Once I put that in, hopefully all will be good and I'll be able to close up the center console and (gasp) drive my big cat once again. Thank you for the suggestions. Even though it may not have been relevant in this case, it's good to know more about my Cat in case that does come up in the future.