(See my other post: Transmission Fault! No code)
2000 XJ8 <89K miles
Symptoms: TRANSMISSION FAULT - AMBER LIGHT ON
Only have 4th gear (& reverse)
Indy mechanic read Transmission code: “1605 Transmission Control Module Checksum Failure.”

I need to replace TCM.
I want to DIY

I discovered access is easy. Passenger side engine compartment near windshield. Remove 1 screw (See photo) from plastic engine cover. Pull cover out & up to remove.
Now see large waterproof box (containing the TCM & ECM)
Remove 4 Torx screws (Mine were fairly loose! But, mechanic had told me he did NOT open box up & look @ TCM) Need T-30 bit. (My top cover stuck as I pulled it up & off.) See photos. TCM is the smaller, vertically mounted box, with the wiring harness on top. The larger ECM is horizontally mounted box. The ECM is just sitting there, in the waterproof outer box, attached by wire harness & easy to rotate up 90 degrees out of the way to access TCM. No need to disconnect ECM wires! In the photo you can see the wiring harness for the TCM with a screw on top. My screw looks partially stripped even though I did not touch it. I am not going to remove my TCM until I have a replacement TCM in hand.

I will post more photos at that time along with any details.

I am not sure exactly how to remove the wiring harness from the TCM. Do I remove that screw? Do I lift up that silver metal bracket? wiggle? pull?
Lady Penelope probably knows. Any tips much appreciated. I don’t want to break anything disconnecting the wires.
See TCM label in photo.
From my photos:

Small labels:

GCJK3R2E65
&

0260002704

Large main label:

Bosch D85
Transmission controller GS8.61.14

0 260 002 704

ZF 6058 002 019

LJD 2401 AB

001 191C0303

GCJK07002044

Made in Germany 082

Last 6 digits of my VIN: F14825

Many places to buy a used TCM. I see prices from ~$40-$90.

I know I must get one with the “Right” numbers. Hopefully, someone can tell me which numbers from my label must match the replacement TCM! I know I cannot use just any TCM from any 2000 XJ8.

I’ve read that I will not need to reprogram the replacement TCM. S/B plug & play.
However, I found this thread from 2012:
————————————————————————————————
Programming a TCM for an x308
XJR-99
1-20-2014
Adapation procedure for MB 722.6 ( X308 4.0 XJR / 4.0 XKR ):

Simple way to reset the adaptation:

1. Turn the ignition key to the on (not start) position.

2. Press the gas pedal to the floor (depress kick down switch) and hold for 10-15seconds.

3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.

4. Wait at least two minutes for ECU to reset.

Keep drivers door closed the entire time.
—————————————————————————
In that thread someone posted:
“There's no need to perform any adaptation on a TCM. If you remove a battery or a TCM fuse the TCM will re-learn very fast.”


https://www.jaguarforums.com/forum/x...cm-x308-51803/

——————————————————————————————
So, Do I:
remove negative cable on my battery
remove wiring harness from my old TCM
attach wiring harness to my replacement TCM
reattach battery negative cable
Is it that simple?

Do I need to find & pull a TCM fuse?
Do I need to follow the 4 steps (Adapation procedure) from that 2012 thread?


I was wondering where best to buy the used TCM when I remembered I had used
https://modulemaster.com/rebuilds/
To rebuild my ABS module in 2012. (I had Jag dealer remove & replace) On their website they said for Jaguar XJ8:
“This rebuild is currently UNDER DEVELOPMENT
Click the link below and fill out the repair request form. Rebuild price (if repairable) $75.”

I figured if they rebuilt mine, it would it definitely be the correct one and it would be tested… unlike the used ones I can buy. I submitted a repair request.

Got reply that they can “try” for $150 + shipping both ways. But cannot test it! They will look for bad solder joints & faulty components on the circuit board.

I also contacted ASI Automotive Scientific Inc. but, they have not yet replied.

So, I think I’m back to just buying a used one from ….someone.
I do need to know what numbers must match.

Any comments or tips appreciated!

 

Don't forget to disconnect the battery first.


Find the VCAT list near the spare tire to get the numbers which should be matched for an exact replacement.


You may get a wrong part message and have to take it to a shop with IDS/WDS etc. software.

 

I was going to remove the negative battery cable. I want to know what the correct #s are so I can question the seller, b4 I tell them what #s I need.
For example, if bc mine says: “LJD 2401 AB”

Maybe some XJ8 TCMs have different “LJD” #s & I need one that has the LJD # 2401.

Obviously, I don’t know.
I really thought having all the #s from the actual TCM label available, would be enough to specify what I need.

I looked under the floor in the trunk & I see no VCAT list. I looked all around that area & even in the battery compartment next to it. I see on both R & L sides of the trunk lip the VIN #, That would have been a good place to put this VCAT list. Surely, Jaguar did not place the list UNDERNEATH the actual spare, requiring you to lift the spare, merely to see some numbers? That would just be mean.

I’m beginning to think that replacing the TCM is not common.
If it was, there would likely have already been a few threads detailing this job here.

Thanks!

 

Steve the VCATS is on the spare wheel well, you may have to pull carpet to actually see it,
'behind the trunk trim on the left hand side of the spare wheel well'...
See this pdf. document for more info...

To explain Jaguar part #s....the LJD I think is model year, then the part, then the program.

 

I found the VCATS list. (See photos)
Note: when replacing the Left side trunk carpet liner do NOT attempt to put it back inside out! —Don’t ask me how I know)

Per VCATS: TCM. LJD 2401 AB/001

So, it is the same # listed on the TCM label that I originally posted.
The only difference is the addition of “/001”

Can I assume that the /001 is not important to finding a suitable replacement?

Searching eBay sellers I see the seller always lists the number & often has a photo of the actual TCM.
Always in a similar format to mine: LJD 2401 AB, 3 letters, followed by 4 numbers, followed by 2 letters.

I found one that is “LJD 2401 AB” just like mine. Also most of the other numbers on the TCM label is the same as mine.

Mine:
Bosch D85
Transmission controller GS8.61.14
0 260 002 704
ZF 6058 002 019
LJD 2401 AB
001 191C0303
GCJK07002044
Made in Germany 082

Used one for sale:
Bosch D85
Transmission controller GS8.61.14
0 260 002 704
ZF 6058 002 019
LJD 2401 AB
001 191C0303
GCJK075001660
Made in Germany 082

I’m guessing that last # (GCJK075001660) is the serial #.

My Jag is 18 years old yet, when I opened the waterproof compartment the TCM looked clean & new. The seller’s TCM looks dirty, label stained & old. Probably doesn’t matter but, I think the location protects the TCM from dirt/grime, etc. Why is that one very dirty?

Seller claims it is “tested” & works but selling it “As is.”

I wonder how exactly can it be tested?

I’m tempted to go for it.

I doubt I can buy a used TCM & know that the donor car’s VCATS label also had the “/001” after the LJD 2401 AB. Unless I physically go to a salvage yard, find an XJ8 that still had the TCM in place & check the VCATS label myself & remove the TCM myself.

So, anyone have answers to my question re removing the wire harness? I wonder if that silver part lifts up like a lever & then maybe you pull?

I will, of course, disconnect the battery b4 I remove & replace the TCM.


Do I need to:

reset the adaptation:

1. Turn the ignition key to the on (not start) position.

2. Press the gas pedal to the floor (depress kick down switch) and hold for 10-15seconds.

3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.

4. Wait at least two minutes for ECU to reset.

Keep drivers door closed the entire time.

&
Do I need to find & pull a TCM fuse?

BTW, I test drove the car yesterday 14 miles & no Transmission error & shifted just fine. I checked with OBD-II & no codes but mine tool does not read Transmission codes, only Engine codes.

Apparently, it resets/fixes itself & then the problem will reoccur.

Thanks,

Steve

 

The XJR Mercedes trans has an adaption process, but the XJ8 ZF trans does it automatically, so no need.

To guarantee a successful swap the (01) needs to match....you've figured most sellers are unaware of the VCATS. This can cause frustration and a few modules before a winner is fitted....are there any 2000 MY cars being broken by forum members that can check or forum sponsor vendors?

A dirty module is down to the breaker, dirty hands and not giving it a clean once removed - the other thing to be cautious of is outside storage from water ingress.

Removal is gently lifting the metal cam lever to unlock the connector, I don't think the screw needs removing.

Also, are there any indy specialists around your way Steve that might be able to do a reprogram if your replacement needs it?

 

Good to know I will not need to do any adaptation process since I have XJ8 with ZF transmission!

Thanks for the instruction to gently lift the the metal cam to unlock the wiring harness connector.
Now I’m concerned about sellers storing the TCM outside & letting it get wet.
Also very concerned about the /01! This means Mine may need to be reprogrammed. I can’t do that. Yes, I have an Indy out here, offered to sell me a TCM for $250 & charge 1 hr labor to do the work. Unless I have trouble with the harness, I can probably DIY in 15 minutes working very carefully & slowly. I can buy a TCM “LJD 2401 AB” (with unknown /xx) for $30-$50 off eBay.

I’m not sure I will know if it needs reprogramming or not. Unless I immediately have worse transmission issues or error messages, I guess I would drive it & wait to see if I get the same exact Transmission Fault with the limp home 4th gear issue.

If I have the same problem, how will I know if it is bc it needs reprogramming or if the TCM I bought has the same defect as my old one or maybe there was nothing wrong with my old TCM & the issue is something else entirely that a replacement TCM would not solve, anyway?
I am basing my need for a new TCM on the Indy mechanic reading the Transmission code: “1605 Transmission Control Module Checksum Failure.”

Since it has “fixed itself” 2-3x now, I know it is not a mechanical problem with the transmission & that is what the Indy mechanic said to me.

Maybe I should look for a TCM that not only says: “LJD 2401 AB” but looks clean? Also where they have a return policy if it does not work. I guess I can ask the seller if they still have the car & can they check the VCATS list & read me the numbers after the “/”….

 

More info on replacement TCM.
Per Jaguar Dealer Parts Dept. TCM for 2000 XJ8 is NLA (No longer available) When it was available, it cost $1,200.00. So, it did NOT cost $2,700 new from Jag dealer, as my Indy claimed! He had offered (If I got the fault again) to sell me a used TCM for $250 & install it for 1 hour labor charge. I asked the parts guy if the #s after the slash were important or if I could ignore them. I explained that I now must buy a used one & I see used TCMs with the same # I have on the TCM label itself but not the additional /001 I see on the VCATS list.


On my TCM label: LJD 2401 AB
On VCATS list: LJD 2401 AB/001

He didn’t know & transferred me to Service advisor who also was not sure but asked someone else (A more experienced Jag mechanic?)
He came back & said yes, the “/001” is important.

I asked if I bought a used one (LJD 2401 AB) & was not able to know what the #s after the slash were & it didn't work bc it needed programming, will they program it for a 1 hour labor charge?

To my surprise, he said we can’t bc we do not have the “older machine.” He referred me to a different Jaguar Dealer that does.

So, Sean B seems to be correct!

My options are to make calls & emails to every seller of a “LJD 2401 AB” TCM & ask if they have access to the donor car & can check the VCATS list & maybe send me a photo or at least tell me the complete # after “TCM:”

If I get someone who says it is /001, buy it, install it & hope for the best.

I test drove my Jag Saturday for 40 minutes & it operated perfectly with no Transmission Fault again. So, I do not know what will trigger this fault. I do not know how I will know if the new TCM fixed the problem. I do not know how I would know if the new TCM required programming.

I am basing my need for a replacement TCM on the Indy reading the Transmission code: “1605 Transmission Control Module Checksum Failure.”
And telling me if that it does it again, Need to replace TCM. It did it again only 8 miles after I left the Indy shop.

Thanks,

Steve

 

Well it sounds like you're on top of it - if it keeps doing it, then yes it's likely a module fault, but I have to ask, how old is your battery? Has the trans been serviced at all?

With regards tracking a module for replacement - your armed with all the info - a case of nailing one down to install.

One thing to try, and it seemed to work for another forum member (but with a MB trans) was to unplug the module from its harness after battery disconnection. Then plug it back in after a coffee - this clears any stored values (and potential glitches) This runs down capacitors for the ROM, resetting the module back to factory fresh - worth a shot.

 

As I said on another thread -- nothing more frustrating or difficult to figure out: intermittent fault.

You keep going back to the indy -- and blaming him for not driving the car longer. But he drove the car for 8 miles -- enough for the car to reach operating temp and to go through all the motions ... he gave you his opinion .. and some knowledge. Some problems don't have easy answers. I had a new Mercedes that MB replaced more modules trying to figure out -- don't want to think about it -- but they had no choice and just kept replacing until they fixed the problem. Had it been out of warranty -- I don't know how it would have been fixed.

Also -- parts prices change both up and down. Your independent may have had someone come in and report that a dealer wanted X to do a fix and he is remembering price on that.

The best you can do is monitor the problem and see exactly what is happening when the problem occurs and get the codes immediately. If its working now you have no choice but to drive it.

I was having RP/ FSE problems -- everything coming up was directed to the Tbody. The car was stuck at my winter weekend house -- many codes. It would not idle or move ..... So, I got to thinking when do I have the problem ... often coasting to a stop sign. What's occurring at that moment -- low engine speed -- brake lights on. Possibly AC compressor cycle -- My headlights on. I discounted the battery and charging system because my numbers were all good -- battery relatively new (3 years). Having other cars that use the same battery -- I bought a new one and took it to the house figuring what do I have to loose ... figuring I would call a tow truck. Started the car and got all the lights -- car would not idle. Switched out the battery -- cars started as normal ... I drove the car home and its never come back .... That was a couple years ago. Still can't explain it ???

And, I was about to have the car towed and a new 2k Tbody installed

 

 

Battery is a few months old AGM, fully charged & load tested & good

I like the unplug/wait replug idea. I will try that!

No, I only went to the Indy 1x & he said he drove the car for 17 miles but, on the paperwork & from my writing down mileage when drop off & pick up, it was only driven 4 miles. I think if he had driven the car 8 miles, he MAY have had the problem reoccur, just as it did for me, when I left his shop & drove 8 miles on the way home when problem reoccurred. Most likely, had this happened, he would have replaced the TCM with one of his used ones for ~ $400. Maybe he would have reprogrammed the TCM, IDK. Maybe it would have been fixed then, IDK.
He may be a great mechanic & this may be a great Indy shop for Jag. I may, in fact, go back there for this or other issues. Some of the $ discussions have raised warning flags (BS alert!) for me. Not just what I posted here. Not really that relevant. (I probably should not have mentioned the price of the "NLA" TCM vs. the price the Indy said it was.)

I did not get any code myself. I only have an OBD II code reader that gets only check engine codes. The Indy read the Transmission codes & told me he got “1605 Transmission Control Module Checksum Failure.”
Also he got a brake switch code.

He said the Transmission problem I described & the fact that it 'fixed itself" points to the TCM.

I didn't mention the brake switch code bc I do not think it relevant here.
FWIW, 1n 2012 @ ~ 65k miles I was getting several error messages, I think they were ASC/TRAC not available & cruise control stopped working. I researched it & others fixed this by replacing the brake switch. I brought car in to Jag dealer & they found no codes but, agreed it was worth trying to replace the brake switch. They did it for ~ $165 & I never had a repeat of that same issue since. Only the Transmission Fault message. Or currently... No error messages.

Thanks!

 

I did what Sean B suggested 2 days ago.

Disconnect battery ( for 25 minutes)
Disconnect TCM (for 15 minutes)
No Transmission Fault Error message when I pulled car FW 20 feet B4 doing this or afterwards, when backed it up 20 feet.
I then test drove car 40 minutes mostly ~ 50 MPH very light traffic with few stops. I then idled 5 minutes outside my house. (The last time I had the Fault was after driving back from mechanic & idling 5 minutes in fast food line) My Jag operated perfectly, with no Transmission Fault again. Same as it did last Saturday. I’m going to start using the car again & see what happens. What is interesting is if I had replaced the TCM, I would think that no TF message meant I fixed it. Now, if no TF message I will hope that unplugging it, reset it as Sean mentioned. I know if I need to replace the TCM, I can easily do it. Whether I will have to go to a mechanic or to Jaguar to have them reprogram the replacement TCM is unknown.

Note: Had to lift TCM up & out to lever the metal clip up. Then, I wiggled & pulled the wiring harness straight out. It came completely out, except was held by far end (w/o any teeth engaged.) By wiggling I got the harness completely off. See photos.
To reconnect TCM is a bit tricky. There is a hinge on the end & the harness must push back to lock into the hinge with a click & only then can you gently push harness down so, all the many teeth engage. Do not force it! It then looks as if one side (opposite the hinge) is not fully down. That is OK. When you push the metal lever back down, it lowers that end of the harness so it is evenly attached to the TCM. It is also tricky to put the TCM back into place. There are flanged edges on R&L side that must go behind vertical ‘columns’ in the box. So, the TCM is actually secured into place more securely than I had originally realized.

 

I think you just need to drive it and see what happens

 

Yes, That’s the plan.

 

Not fixed!

Drove 27 miles today & @ 15 miles Transmission Fault & stuck in 4th gear again.

I’ll need to start calling TCM sellers & ask if they have access to the donor car & VCATS label.

Too bad.

 

A X308 I looked at at the salvage yard has a LJD 2401 AB but no /001 following that

Was there a warm up time before the fault accured as this may point to a shifting solenoid wingdings opening up and valve porting to the unenergized position dropping it back out of 4th . Common mode of failure as the solenoid expands in size with heat and the winding wire opens up a gap .To test this You can read all 3 solenoids at the same time at your time of failure at the ECU connector and the normal winding resistance is listed in the transmission manual but they all should be about the same . Easy DIY replacement of the suspect solenoid and they're available through the local parts store . Your check sum failure may be a secondary issue or since it can't calculate or come up with the same resulting command it drops your 4th gear as a default as this prevents the engine from stalling out if the ECU command is for too early 4th

 

Lady Penelope,

Did you look @ the VCATS list under the trunk carpet (See my photos) On the TCM itself it would only list: “LJD 2401 AB” Along with serial #s & many other numbers -see my photos & list.

However, on the VCATS list, It surely had LJD 2401 AB/???

What were the #s after the slash?

(You likely already know all this) I wonder how many different #s after the “/“ are possible for an X308 & especially if it is a TCM with the LJD 2401 AB? IDK if the possibilities are only ; 001 & 002 …which would give me a 50:50 chance assuming the seller cannot check the VCAT list. Or: 001,002, 003,004, 005, 006 ,007 & 008, etc. Then it is highly unlikely I can find a LJD 2401 AB/001.

To answer your question (finally!)
Yes there has been warm up time when this Transmission Fault occurs.
However, after it occurs, the next time I start the car, it usually immediately has the fault. When it 1st happened, I let the car sit overnight & checked & had the fault immediately. I had to make a stop on the way home yesterday & car was parked for ½ hr. & when I returned & immediately had the fault. I have not started the car since I parked it in the garage yesterday.

My best guess is If I go out now & check it will have the fault immediately but, if it does not I would only be able to drive it 10-30 mies b4 the fault reappeared. But maybe I could do several 25 mile trips, over a few weeks, b4 it reoccurred, IDK.

RE you test of the solenoid suggestion.
How, exactly, do I read all 3 solenoids @ the ECU connector?
Do I use a multimeter?
I’m looking at my photo of the ECM, next to the TCM, b4 I rotated the ECM out of the way to photograph the TCM label.
It looks like there are 6 white, plastic wire harnesses, plugged into the side of the ECM, facing towards the front bumper.

I don’t know where the 3 solenoids for the ECM are located. Must I disconnect the battery, disconnect & remove the ECM, open up the ECM… in order to do this test?

I hope I can learn how & do this test & one of my solenoids is bad!

Thanks!

 

Steve, there could be a fault with the solenoid block fitted in the trans, all the A drum issues stem from the wear inside this block from the solenoids, one in particular wears a shoulder and sticks, leading to a pressure spike and the hard shifts, eventually busts a circlip that releases the A drum.
One thing can be done and it's the Transgo kit, alternatively a new solenoid block and kit.

 

Editing
This is for a normally aspirated engine for 2001 and will have to verify effective transmission model as there was a change in 2002 ( ? )

Will have to look at the VCATS list .

While you are in the area if you remove the valve body by removing the transmission pan I would recommend the TransGo regulator mod kit that includes the step up a size reamer as a insurance policy against the expensive damage if the pressure regulator fails .

The connector map is for the module side and the harness to the transmission connector is a mirror image .

Just disconnect the battery and leave the transmission ECU alone as you are reading the transmission itself .

Look for resistance between Black - Red , Black - Blue , and Black - Green . They should be the same around 55 ohms off the top of my head . You might even find a bad one without warming them up as you describe your fault accurateness .

See page 28 and on :

https://www.zf.com/global/media/zf_m...sa_4/5HP24.pdf