Good morning all !

Happy owner of a Jaguar Type-S 3.0i phase 1, I find that the J-GATE format lacks precision.

By analyzing the documentation of the gearbox (Ford 5R55N), I understand that it accepts to be in semi-automatic mode. The only problem is that J-GATE does not allow it.

I’ve read on many forums of people debating the relevance of a semi-automatic mode, but I would like to focus here on the technical possibility of doing so.

Here is a link to the complete gearbox analysis in PDF:
https://shop.ukrtrans.biz/wp-content...logs/5R55N.pdf

We can see at the bottom of page 10 that it is possible to be in a semi-auto with the + and - signs.

I read on another forum (unfortunately I can no longer find the link ...) that the gearbox management module is the same as that of the engine.

I told myself at the beginning that it would be simple to block a speed on the gearbox by directly connecting a RaspberryPi equipped with a relay card to contact the corresponding relays for each speed. I quickly understood by reading the technical review of the gearbox that there is much more than just relays. So I dismissed this option.

I think that the only way to force the gearbox in semi-auto is to access the engine and gearbox management module (by its data bus?) And to be able to reprogram it by adding the possibility of intercepting a command sent to the OBD bus to select a speed.

This involves hacking the OBD bus and reprogramming the computer. I am aware that it is not simple, or perhaps even doable, but I am interested in any useful information.

If anyone knows a little more about this issue I would love to learn more! Thanks in advance !

 

I'm wondering whether your J-gate is not functioning correctly or if you may have dismissed the J-gate on what looks to be mistaken beliefs.

I've no idea what "I find that the J-GATE format lacks precision" means.

 

Hello JagV8,
thank you for your support my J-gate is functionning great. Sorry if i'm not clear, english is not my native language.

Too make it simple : i don't like the kickdown. I don't want my engine to go to 6500rpm for overtaking a truck. I drive an Opel Astra with auto gearbox as company car with semi-auto mode and it's marvelous. I'm sure it could be better to use the entire torque of the v6 than making the engine yell for nothing.

You'll replie : press the pedal gently, yes, it's what i'm doing, but when a compare to my Opel, or a tip-tronic from a friend, the S-type, the lack of semi-auto is a big flaw.

 

I'll reply use the J-gate.

(I don't have any problem along the lines you mention of course, as the STR is a bit of a beast.)

 

It doesn't solve the kickdown issue :S

 

The ZF gearbox was a big step up from the Ford 5R55N one, especially when mated to the V6. My experience with the 5R55N was similar - reluctant to change down then all of a sudden two gears down and a load of revs but missed the overtaking opportunity. Apparently, this is how it is supposed to work. Check the handbook for more details.

"It doesn't solve the kickdown issue :S"

Maybe it actually does: Selecting 4 on the J-Gate may be enough - it will drop from 5th to 4th and you will have some more revs for acceleration without ending up at the red line too soon. If the revs are still too low, flick to 3. I guess it is a matter of getting used to how it works to make the most of it.

I ordered the manual and nearly 20 years later, I still like it!

 

In what way does it not do what you want (as contrasted with what you have stated).

 

Thank you for those informations neilr. Selecting 4 or 3 on the J-gate helps, but not completely as you said.
I wrote to some workshop for reprograming the PCM / TCM but they all says that's it's not possible.

 

The PCM (Powertrain Control Module) is both ECM and TCM in a single unit.
Ford did NOT want to pay for the CAN bus so chose the incorporate the modules into a single without external network.

The PCM can certainly be 'REPROGRAMMED'. Jaguar issued a TSB for the procedure.
I did perform this when I worked at the dealer when these cars were introduced.

WDS or IDS will have the software to do this.

bob

 

Hello motorcarman, thank you for your reply, this is very, VERY interesting !
I have read you .pdf file, so it reprogram the PCM to solve harsh shifts, is there a way to know if this update is already running on my PCM ?
They use a software called WDS release JTP759/14 with an update file to push to the PCM, do you think it's possible to access the source code of the PCM to modify it with this software ?

Do you have a release of that software ? Is it possible to send it to me ? How do you link it to the jaguar ? I already have a carsoft i930 reader jaguar / land rover but I don't have serial cable. Sorry for asking many questions but it's really interesting.

Thanks !

 

Perhaps you could try a bit harder to explain what you mean?

Hint: the shorter and terser what you say, the less help you can expect - as you can see.

 

WDS CD14 is really old and I doubt anyone is running that software. The TSB is requiring CD14 OR LATER software.

The last WDS version was CD43 and IDS STARTED with version DVD42 so any WDS/IDS you find will probably be later than version 14.

Can't vouch for SDD because I don't use it.(it might revert to Legacy IDS for the programming?)

When you attempt to reprogram the PCM it will usually display a text box to indicate the software already configured and the software about to be configured and asks "DO YOU WISH TO CONTINUE?

If the software is already the latest the 'text-box pop-up' will indicate this.

 

Okay thanks for the informations, I bought on ebay the latest version of IDS (activated) and a J2534 OBD cable. Waiting to deliver it, but there is delay because of the covid-19.
Even if I can't reprogram the PCM it's a good thing to have the software.

@JagV8 : Take a drive in an Audi with TipTronic or Peugeot EAT8, you can lock a gear, and even if you push the throttle at max while you are at 2000rpm 5th gear engaged it doesn't downshift the gear to the 3rd. On the 5R55N, it does, and it's annoying because I know it's only a software lack and it's not a good thing for the engine. I want to use the torque, not the horsepower.

Sorry if I'm not clear, trying my best but it's technical and i'm natively french

 

I can't see any point comparing an old box like the 5R55N with the Audi one.

(Also, it sounds like I would want it to shift anyway in that scenario.)

 

I drove a tiptronic from 2002 and it can lock a gear. So I think that it can be compared. Or it seems that Audi / Peugeot / Opel / GM is better than Jaguar
Funny to know that Ford released the 5R55S with SelectShift, wich is basicaly the same gearbox but with the semi-auto option ..

 

Well you're looking at a box that was quite old when the car was being designed in 1998 or earlier.

(The 5R55S looks to be years later - by which time the ZF6HP26 was out and frankly much better.)

I think trying to do what you want would require a serious re-write of the PCM code and it's commercially secret code...

Also, the re-write isn't bound to be possible e.g. it might not fit in the available space.

 

Jaguar obviously made the decision that you can limit the up shifts with the J-Gate selection but if you needed even more acceleration, kick-down was still available, which is a fairly natural way of driving for the typical driver. For example, limit the high gears for hilly terrain, but still allow a quick down-shift for rapidly pulling out of a sharp, slow bend.
Avoid kick-down by not completely depressing the accelerator and you should get the type of acceleration you are looking for - in the gear you have selected. It isn't worth trying to change the software for the small difference in behaviour you are looking for.

 

Thank you for your answer JagV8 and neilr.
I know it's not worthing it, but I'm curious and stubborn.
Maybe another way to have a throttle more precise is to change the pedal with something that offer more resistance. It's sometimes complicated to gauge the power on the pedal to not have the kick-down as neilr said.