Send it to ASI they can fix it at a fraction of that price and you do not need to reprogram it when you get it back. Just disconnect your battery remove the module fill out the forms on ASI web page and send it to them. You do not want to drive it this way you could cause other problems in the trans.

 

In looking at the ASI website it does not show that they can repair the TCM from my 2006; can they?


Just where is the TCM located at? Internal or external of trans?


Thanks

 

ASI can repair a lot of stuff so I would call them and see what they say.

On the right side under the hood at the fire wall lift the panel and under it you will see a large box and under that cover is the ECM & TCM. You have 4 screws holding the cover on. In this photo I have the cover off and the silver box is the ECM and one forward of it with the wire plug on top is the TCM just lift the silver tab and the plug will become unlocked, lift it off then lift the TCM out. Be sure to disconnect the battery first.

 

Thanks again Gus.... got it.


Dealership says that when TCM is replaced the valve body is also required, do you know why this is?

 

They may be under the impression that the valve body is suffering with a problem. If I were you and I have done this get the TCM checked and repaired by ASI first then drive the car if the problem still exists then look into the valve body. If the TCM is replaced it may need to be reflashed or programmed.

 

Gus, big problem... the TCM is not located as in the picture above! Jag moved it at some point in time.... no idea when...bit not there in my 2006 XK8.
It maybe under the ECM but there is a special bolt holding the ECM connector, similar to a security torx but larger center pin, that I cannot remove in order to get the ECU out and see if the TCM is under.
I am stuck!!

 

Let me look into this and get back with you.

 

It is part of the valve body from what i can find. Check your PM.

 

Much to my surprise the TCM is mounted on the transmission valve body inside the trans for your car. I called around and found out that no one has taken on a repair of that TCM but you can get a reconditioned valvebody with the TCM for about half the price you were quoted. The TCM can be removed but would need to contact ASI to see if they can work on it.

 

I have been researching this as well.... and yes TCM is part of the valve body, all one piece. Dan from JagBits sent me a parts diagram that shows everything and at a much better price. However the TCM requires to be flashed and that requires the dealership...... so looks like I am stuck with a $4500 repair bill... once fluid, labor and taxes are all added in.


Anyone want to purchase a low mileage XK8 that needs a "minor" repair?!!!!!

 

And the code you are getting is about communication errors between the ECM and the TCM. Have you checked the connector on the side of the transmission? It is a round plug that needs to be unlocked to be removed. I would take a hard look in that area for any sign of problem with the wiring (follow it as far as you can) as well as any fluid leak (this is not uncommon for the trans to leak from the sleeve around that connector). In addition, it seems that the exact procedure for putting the connector back calls for pushing it in, with no twisting motion. Separately, it seems that on occasion, it is not entirely impossible to push some of the pins back into the trans, and obviously cause connectivity issues. Some of us have ordered parts from here:

CTSC FAQs

Their FAQs have nice PDFs that describe what I am talking about. The owner is reputedly very knowledgeable, if you can reach him, and might be able to help you eliminate other possibilities before replacing expensive parts that normally have a good reputation. Best of luck, keep us posted.

 

I would still call ASI and see if they can repair the TCM that would eliminate the reprogramming.

Gus
www.jagrepair.com

 

I will get under the car this weekend and check the connector...good idea.


Also worth a call to ASI..although not real confident about removing the valve body. Last time I did any auto trans work I installed a shift kit into another vehicle and it did not go well.


Thanks for the replies.

 

From what I understand the TCM can be removed separately.

Gus
www.jagrepair.com

 

CTSC's FAQs has a PDF that describes how to remove it. It does not seem that involved once the car is properly lifted. The transmission stays attached to the car of course, and it all comes out the bottom. Your car being an '06, you probably have the nice larger Torx bolts to the pan, making the removal that much easier (my '03 has the small bolts that strip as soon as the Torx bit comes out of the toolbox). Nothing is really in the way of removal. Once removed, check the big magnets on the pan for any signs of metal shavings, and check the fluid for clarity and burnt smell. At this point, you might want to think ahead and look for a replacement pan/filter and fluid. Folks have reported great results with the cheaper Dexron SP...

Also, if you go down that route, consider reaching out to CTSC (or any other ZF technical place) to see if they could bench test the valve body. This could tell you if it needs repairs to begin with.

Also, another quick test: If you move the J-gate left to "5", instead of "D", is there any difference? I am trying to gauge if there is a problem with the micro-switches. Unfortunately, 50Mph is probably where it switched from 5th to 6th, so forcing it to 5th is not helping. Here is what I am thinking: clear the codes, run the car in "D" for a while and see if/when the code comes back. Clear the code again, drive in "5" for a while and see if/when the code comes back. Maybe there is a clue there.

Finally, I trust you have eliminated all the easy scenarios like aging battery, water in the firewall bins where all that electronics lives, loose ground straps and loose/corroded ECM connector. Quite frankly, maybe a "hard reset" would not hurt at this point.

Best of luck, keep us posted.

 

Lanny, I have a similar problem on my 2002 XK8. It is intermittant and only on light throttle openings. I was told when I had a Honda CRV to be very carefull cleaning the TB with any solvent as it can get into the spindle bearings and wash out the lubricant. Is there anyone who can repair TCM's? Saying that I am still unable to source a security module!!

 

How do I know which ZF trans 6HP?? trans I have?


I did get under the XK8 this morning and checked the connector coming out of the trans...only found one with two wires; purple and yellow; contacts were clean. I did not find any round connector. If it was there it was not accessable due to the exhaust. I assumed that these wires were the com wires to the ECU.


The surging occurs in either auto or manual sides of the J-gate, did not really matter what engine RPM or gear I was in. Seems to have gotten worse this past week as it starts surging quicker than I remember.


The thought is to return to the dealership and have them attempt a re-flash of the TCM, although they have warned us that this could make the car non-driveable as it depends upon the TCM failure.


The TCM is not available without the valve body, so would have to purchase the "kit."


Have not called ASI to see if they can fix TCM....will do that on Monday.


Took a good look at the trans this morning and all pan bolts look accessible.


I will read more on what CTSC has regarding removal.


Thanks and I will keep this updated.

 

Going to start a new thread as the problem is the transmission, not the throttle body.

 

Our car have a 6HP26. If you check the CTSC web site, there are pictures that show where the actual number plates are on the trans. As you can imagine, this trans was used on many cars, and there are differences among them, i.e. I am not sure a 6HP26 for a BMW fits our cars for sure.

On the driver side? That is most likely a temperature sensor. The actual ECM-TCM connector is on the passenger side, towards the back of the transmission (near the output flange and the drain plug), fairly high up. It is somewhat masked by the exhaust pipe and heat shield. It is at least 2" across, black plastic with a taped wire bundle coming out. Use whatever works to do a thorough check: mechanics mirror, even a mobile device camera, or Facetime/Skype with a second device. Try and follow that wire as far as you can to check for damage. Check for leaks (there is a cheap sleeve to fix a leak there). Try and pull it out and check for corrosion or pins out of alignment. Has this been messed with ever (transmission service,...)?

Another (cheap) shot in the dark: check that the ABS reluctor ring on the driver side rear hub is solid with the hub. There have been many reports of that ring being loose and causing major problems (basically the car does not know its own speed so it cannot determine what gear to be in). This is typically accompanied by other codes, but it is worth a check. Remove the driver side rear wheel, locate the ABS sensor, and reach under it for the ring. It has peaks and valleys and should be around the axle, and SOLID with it, not loose. Most likely not your problem, but easy enough to check.

I know there is no easy phone number, but try and reach out to a ZF specialty shop like CTSC for a second opinion. The owner is reputedly very knowledgeable and more than likely will steer you in the right direction.

 

Found the CTSC web site and the diagram that shows the numbers plate...will get under the car sometime this weekend and take another look.


The only connector I saw was at the front on the trans. I will look again for the large round connector.


I will also check the right rear wheel ABS reluctor ring....heck worth a look!


Thanks