Hello all !

My Jag, XJ8 from 2001 seems to have a TCM problem.

As soon as i switch the contact on, I get Gearbox Fault and other transmission related mentions on my center console as well as P706 on my obd. I need to restart the engine several times and pass thru all gears before the mentions go away. Then, when I drive about 25 Km, all remains normal as long as I do not shift back and keep it in D.

Someone told me my TCM is DEAD.

I find as much TCMs as I want on the .net but often with the mention: may need to be reprogrammed for your car.

The 3 Jag garages around me are each at least 150 away, and all tell me my car is too old to do anything to it and ask if I do not aant to buy a new Jag. NO, I do not want to buy a new one !

Does anyone have an idea about that possible "reprogramming" of my TCM ?

I have a picture here of mine:




Can anyone help. please ?

Thanks,

Takeo.

 

The few times I’ve replaced a TCM on these cars, reprogramming was never required. When you get another one, just be sure to clear all the codes out and you should be good to go. You could also try unplugging the TCM and simply reconnecting it a few times to see if micro-corrosion is a potential. Yes, it’s thing.

I would also check to see if you have any transmission oil leaking into the range switch on the right side of the transmission.

I’ve also seen P0706 happen because the shift cable needs adjusting under the J gate. If you put the lever into ‘N’, you should have equal amounts of play gently moving the lever up and down while observing the ‘N’ as the center point.

 

VCATS VCATS VCATS VCATS VCATS

Look in the boot for the VCATS label and make sure the replacement matches if you decide to get another.
The VCATS suffix IS the software version!!!!!!!!!!!!!

 

Where exactly in the boot do I have to look please ?

Thanks,

Takeo.

 

VCATS in the boot behind the carpet.

 

Thanks guys, i dont have a garage. As soon as it stops raining I will try all that is read so far.

Takeo.

 

Ok, here I am again, sorry.

So, a couple of hours ago, it stopped raining for a few minutes and, as suggested here, I plugged the TCM in and out 5-6 times, also used A LOT of contact cleaner wherever I could on the TCM and the plug.
Then I took her for a 20 km drive, and:

* contact ON, no error message (usually I get a fault message when turning contact on)
* 30 meters in reverse: error message
* Contact off and back on, no fault message
* Drive 2 Km and she does not take 5th gear
* Drive 1 Km more, fault message
* Stop, contact off and bacl on, fault message gone
* Drive again, no more fault messages, she takes her 5th gear !
* Drive 5-6 Km more and stop on parking space, contact off
* Wait 10 mins engine off
* Contact on, no fault message
* Drive 10 km home, no messages underway, takes her 5th gear
* 150 meters from my home parking spot, I drive over a sewer lid, very small vibration and fault message !
* Stom, contact on and off, no messages till I stop at home.

So, I conclude that there must be a simple contact fault somewhere, I do not understand the small sewer lid vibration that leads to a fault message.

I have been thinking of SLIGHTLY twisting each pin of the TCM plug. 3 degrees or so. Maybe that could give a better contact in the TCM ???

I also checked all wiring for rodent damage: NONE.

So, this is my TCM adventure so far. It also proves, I think, that the TCM itself has no problem, but that we have a silly contact problem somewhere ...

Thanks for reading and answering if you like.

Takeo.

 

Until you get the DTCs from the TCM (and all the modules on the CAN bus) you just GUESSING at the problem!

 

Dear Sir,
I live in DEEP France, this is 100% rural and one is here very much on one's own.
Jaguar is NOT a popular car here.
So yes, I am GUESSING ! And trying to remedy whatever I can.
Now I will buy a new TCM ..

Sincerely,

Masamune Takeo.

 

@motorcarman , do you know of an affordable scanner to suggest to @Takeo vs buying a new TCM that would communicate with his vehicle so we can better assist?

 

I have two WDS and two IDS Rotunda VCM with DELL laptops.
I used WDS and IDS at the dealer when I worked there. I have not used anything else so I cannot recommend.

Throwing parts at a car can get expensive. It is annoying to find out that something like an inexpensive sensor is the problem after spending huge amounts of money on unnecessary parts.

People have mentioned alternative diagnostic tools but I never needed them when I have the dealer tool.
I have no alternative suggestions. Sorry.

ANYONE tried this?????????????
https://www.ebay.com/itm/31334239505...Bk9SR47zqv73Yg

 

Hello,

Just bought a TCM from Auto Reserve Jaguar. GBP 25.-

Takeo.

 

Hello, I installed the "new" TCM.

Now, I get fault code P1643 (CAM TCM token missing)

Also, new: Incorrect part fitted.

Does not acclerate properly and hesitates while accelerating ...

No 2 cylinder coil replaced, now fires on 8 cyl again.

HEEELP !!

 

Your original fault code was P0706 which refers to the transmission rotary switch, not to the TCM:

So, your original TCM is probably good. I would put it back in and look at the rotary switch.

It appears that the "new" TCM is not communicating with the ECM - Code P1643:

This could be due to the new TCM having different VCATS, thus "incorrect part" (or it is bad ?).

 

M. STOJANOVIC !

Thank you very much ! I have already checked the D4 switch and could no find anything wrong with it. NOW, I will re-try with old TCM and re-check the D switch. What I had found first time all microswitches around the D plate just sat loose, were not screwed or attached in place around the D plate. I thought that had to be that way.

With old TCM: Start engine and rough gear changes. Re-click ignition switch 4-5 times till fault messages go away. Then drive normally for about 2 km and get fault message. Stop and switch ingnition 2-3 times on and off and fault msg goes away. This lasts for some 20-25 Km driving stoppng and manipulating ignition switch. After that, all normal for a long drive but engine braking gave me fault msg again.

I was thinking of a TCM capacitor somewhere leaking and needing a drive and alternator charge. That is why I was thinking about a faulty TCM.

I will put the old TCM back in and re- check the D switch.

Takeo.

 

Helo M. Stojanovic

I just spent a couple of hours inspecting te D-switch and found, under the switch a broken microswitch that is riveted to the instrument chassis.

Drilled out the 2 rivets, and "repaired the switch". It works, but I still get P 0706. Also, cannot start anymore in N.

I am afraid I will need a new or secondhand "cluster" that holds the microswitches in wich new or usable microswitches are available. I have no idea of how the whole think is called is called..

The VCATS of m Jag are here:

 

Hello, got the VCATS of my jag here:





Can you now please tell me what to do with this info or what to check it against ?

Thanks.

Takeo.


PS there was a broken microswitch 3rd from above, riveted with 2 aluminum rivets. I improvised a repair. But all is the same as before, with the original TCM I have put back in.

 

Hi Takeo,

The part number of your TCM is LJE2401AB, and the VCATS firmware version is 002. In my experience, if you replace it with another working TCM with the same part number and same VCATS version, you will not need to do any programming. As far as I know, the VCATS versions over the years of X308 production were 001, 002 and 003.



However, based on the P0706 code you reported, as M. Stovanovic posted, the problem would seem to be related to the cable adjustment or rotary switch, not the TCM.

Cheers,

Don

 

This thread talks about repair of the Rotary Switch: https://www.jaguarforums.com/forum/x...repair-270183/ which may help.
It is for X100 but it should also be applicable to X308.

 

Hello DON,

Thanks for your comments and advice !

My original TCM (back in the car again) is a 002 version and the one I bought and cave a fault reading is a 003. (So I can try to find a 002 version if needed)

Under the plastic "D" switch where the shifter lever goes in, I found a faulty microswitch which I first tried to repair, but, this morning, finally replaced it with a NEW one (CHERRY brand, bought from CONRAD).

A few swearwords later, today, after some "tests", all on a sudden she drove away like new, no more hard shifts, she flew like a bat out of hell.

That lasted for about 2 Km and I got the fault message again : gearbox fault and it went in to limp mode.

Cut the contact, stwitched on and off 2 x and she went good again for a couple of Km.

After that, she stayed in limp mode. Go figure.

But, whatever I do, i do NOT have any hars shifting again !

Engine start 2x, no messages but a s oon as I evn just touch the shifting liver, she goes back into limp mode, max 2000 RPM

BUT, out of gear, she just revs to 7,000 what she did NOT do before I swapped the lil switch.

My test drives: limp mode, stop, wait 10 mins, re-start, normal drive for 2 km, limp mode. Did this 3 times.

I will let her rest till tomorrow now and will try again. (Several times, before, after a night of "sleep", she was ok again for some time).

I will also try to find a 002 TCM

Thanks for your time !

Takeo.