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I've reached that point where I can no longer justify the cost of keeping my 2004 XJ8 on the road. It's a shame really as the car runs like a scalded dog and aside from the paint beginning to show some weak spots it is both straight and clean inside and out. Yet the ECM is bricked with the local Jaguar techs unable to communicate with it and even their go to repair source couldn't get it to talk to them so nothing could be retireved and programed into a replacement ECM. That left me having to consider a VERY expensive new NOS ECM from Jaguar plus the programing necessary to introduce it to my car. While such a unit is available I can't rationalize spending anymore on the car as it is the odd man out. I had bought my wife a Genesis 5.0 so the XJ8 was relegated to standby service.
If anyone in the South East has an interest or a need for a complete XJ8 to either resurrect or part out PM me. I've got a $1000 bill at the shop to pay which I'd like to recover and given the thousands I've spent over just the past 2 years in replacing various and sundry mechanical parts I don't think I'm overly optimistic. If interested I've got plenty of recent pictures and a file full of service records going back some 7+ years.
My suggestion is to ring around the specialist Jag wreckers & see if they have an ECU with the same part number as yours. Check web sites around the world & there is a very good chance that you will find one at a fraction of the new price.
Ok buy the used ECU. It doesn't match the car so the car won't run/disabled.? My local Jag dealer laughed when I asked if they could. What's the solution here?
Ok buy the used ECU. It doesn't match the car so the car won't run/disabled.? My local Jag dealer laughed when I asked if they could. What's the solution here?
This is old tech for the dealer, and they will have forgotten how to do what you need. Find a local specialist that has more knowledge on the old cars and I am sure they will be able to get the SH ECU to play. http://www.jagrepair.com/images/TSB/...ID%20block.pdf
Last edited by Cafcpete; Feb 24, 2021 at 04:55 AM.
I have a 2004 XJ8 for parts, and would have the ECU.
I can get it out and check the part number, unless your mind is made up to stop work.
Rob
Robert, thanks for the offer. I'll check the parts # on mine. If they match, what do I need to do to make it usable for my car? Cafcpete, my problem is that I can't drive to
the local specialist.
Before getting to deeply into buying a used ECM,even with identical exterior numbers and series, you have to understand the nature of the system in your particular year and model as these systems were upgraded almost every year and what may be true of a newer or older model may well not be trueof yours.
First you have to know if your ECM is responding to any commands at all or is it just having a problem controling some normal function. If it is NOT responding or communicating with the SDD scanner (at least in the 2004 model year) your cooked as far as buying and programing a salvage yard ECM. The reason is simply one of not being able to extract any information from the old ECM as to the individual identification needed to get the car to start. If you can't recover the information retained in the VID block of the old ECM and program it into the replacment you may be able to communicate with the ECM but it won't start the car.
In my case the ECM was for whatrever reason stone cold dead and even a used ECM from anothe XJ8 of the same year would not start the car even though we could communicate with it. My ECM which was sent to an outside company they'd used before was not capable of being repaired and they weren't able to extract the VID block info I would have needed in any case. My ONLY option was an $1800 NOS ECM from Jaguar specific to my model, year, and locality and even then it would have required additional programing to make it work.
Everyone I spoke with on thie forum and elsewhere who has had expereince with these damn things has come to the same conclusion. It may well be different for later models as the system of VCATS and VID blocks was changed to make ECM swaps a much easier and less expensive proposition but at least on the 2004 models we're stuck with what Jaguar had designed.
As for my dealer, as expensive as they might be I've been to their shop several times and they have not only the Jaguar and Bosch equipment and programs both new and old but they have 2 technicians specifically trained with Jaguar who have some 50 years between them including one of th men who started the business years ago. This is in addition to the Porsche, BMW, Land Rover business they do as they are the ONLY high end service facility for any of those makes within 75-100 miles of Gainesville. They bent over backwards to try to find a way into the system and what might have caused it to do what it did and this was no 30 minute diagnosis with an immediate jump to an extra $2000-$3000 part just for grins.
So while technically my car is repairable it comes down to a metter of cost and value. The reality is that 2004 XJ8's as nice as they are and as much as I like them are never going to be a collectible classic and with an average real world retail in my neck of the woods of $3500-$5000 it made no sense for me to invest another $3500 - $4000 in a care that was never going to be more than a spare. I'm into this repair to the tune of $1000 so I'll lick my wounds and go on.
Still a great parts car or even a project with a know cost since we were able to find1 remaining new ECM but I'm 74 and don't need another project as I already have more than I have years left to complete.
Before getting to deeply into buying a used ECM,even with identical exterior numbers and series, you have to understand the nature of the system in your particular year and model as these systems were upgraded almost every year and what may be true of a newer or older model may well not be trueof yours.
First you have to know if your ECM is responding to any commands at all or is it just having a problem controling some normal function. If it is NOT responding or communicating with the SDD scanner (at least in the 2004 model year) your cooked as far as buying and programing a salvage yard ECM. The reason is simply one of not being able to extract any information from the old ECM as to the individual identification needed to get the car to start. If you can't recover the information retained in the VID block of the old ECM and program it into the replacment you may be able to communicate with the ECM but it won't start the car.
In my case the ECM was for whatrever reason stone cold dead and even a used ECM from anothe XJ8 of the same year would not start the car even though we could communicate with it. My ECM which was sent to an outside company they'd used before was not capable of being repaired and they weren't able to extract the VID block info I would have needed in any case. My ONLY option was an $1800 NOS ECM from Jaguar specific to my model, year, and locality and even then it would have required additional programing to make it work.
Everyone I spoke with on thie forum and elsewhere who has had expereince with these damn things has come to the same conclusion. It may well be different for later models as the system of VCATS and VID blocks was changed to make ECM swaps a much easier and less expensive proposition but at least on the 2004 models we're stuck with what Jaguar had designed.
As for my dealer, as expensive as they might be I've been to their shop several times and they have not only the Jaguar and Bosch equipment and programs both new and old but they have 2 technicians specifically trained with Jaguar who have some 50 years between them including one of th men who started the business years ago. This is in addition to the Porsche, BMW, Land Rover business they do as they are the ONLY high end service facility for any of those makes within 75-100 miles of Gainesville. They bent over backwards to try to find a way into the system and what might have caused it to do what it did and this was no 30 minute diagnosis with an immediate jump to an extra $2000-$3000 part just for grins.
So while technically my car is repairable it comes down to a metter of cost and value. The reality is that 2004 XJ8's as nice as they are and as much as I like them are never going to be a collectible classic and with an average real world retail in my neck of the woods of $3500-$5000 it made no sense for me to invest another $3500 - $4000 in a care that was never going to be more than a spare. I'm into this repair to the tune of $1000 so I'll lick my wounds and go on.
Still a great parts car or even a project with a know cost since we were able to find1 remaining new ECM but I'm 74 and don't need another project as I already have more than I have years left to complete.
RD, Thanks for the detailed response. Upside is that my car starts immediately and sounds good. Cold start RPM drops to idle. Interesting that RP/Yellow/Red kicks in right after that. All of these indicate an ECM that's at least partially functioning. No codes? Figured a rebuilt ECM was easy enough place to start. LOL. All the companies mentioned in here don't work on Jag's anymore. Changing ECM's sounds like a huge expensive PIA. Based on what I've read and your thoughts, I'll sell the car and buy a newer one (ideally XKR). Gorgeous convertible but it's not worth it.
The big problem is that I can't pull codes (or SDD either?). Seems to be a common problem. I've seen many complaints. Maybe it comes down to tracing the wiring harness. Checking under the steering wheel. Turn signal gets mentioned several times. Also, battery is excellent recent Borsch. Charges to 13.5. However drops 1.0 v overnight so something's happening electrically. I don't want to do "educated guess" repairs (unless they're simple) before I have codes.
Glad to hear your dealer has worked hard to help. Sorry to hear about the $1k. I've talked to the local Jag mechanic. Pleasant, very good at what he does and very popular. They have a long list of customers waiting. I've got a 4/14 appointment. Car gets towed and diagnosed. I decide at that point. Agree w/ your thoughts about numbers of projects and age. Great list of cars and bikes by the way.
You really don't see them becoming minor league classics? They're gorgeous cars that get a lot of attention. I've seen several XK8's sell for 15k. Of course that's the CA market. Years ago, had a 230SL. Fairly easy to find for under 10k. Sold for 12. Now? 30-40 for good examples and a lot more for great ones.
If you get an ECU with matching part number to the one fitted in your car, it should work perfectly. The part number is on a label on the ECU. I did this when I had an X300 XJ & it worked perfectly. It is essential though that you get one with the same part number, as Jaguar constantly upgraded these parts & one with a different part number will not work.
I posted a TSB link earlier which explains how using WDS you can program a replacement ECM. http://www.jagrepair.com/images/TSB/...ID%20block.pdf
This equipment is dealer/ specialist, (or laptop software and mongoose cable) but it can be done.
Extract here
CONFIGURING NEW ECM
When an ECM is replaced, the configuration process is different from the other control modules. Data cannot be extracted from the VID block and downloaded to the new control module, since the VID block in the new module is not programmed.
Once the ECM has been selected and the VIN verification has been carried out, the WDS application will flash program the control module with the latest available calibration file from the WDS database. When the flash programming has been completed successfully, the next stage is to transfer the ECM’s unique Passive Anti Theft System Identification (PATS ID) to the other control modules on the vehicle that require it. The control modules that store the PATS ID vary from vehicle to vehicle.
After flash programming and PATS ID transfer have been completed, the next stage is to generate VID block data. This includes the configuration data for the ECM and the mirror data for all the configurable control modules that are also stored in the VID block.
It is essential that the data displayed during the vehicle identification process at the start of the WDS session is checked and corrected, as this data will be used to identify which control modules the WDS needs to extract data from to rebuild the VID block.
The ECM’s own configuration is constructed from data extracted from the VCATS code stored in the WDS database, for the VIN entered at the start of the session, and from operator questions. The 17 character VIN that forms part of the VID block is copied from the instrument cluster. Once this part of the VID block has been rebuilt the application will interrogate all control modules that store a mirrored copy of their configuration data in the VID block and construct the remaining part of the VID block before downloading it to the new ECM.
The final stage is to clear any DTCs logged, the whole programming and configuration process for the ECM will then be complete.
POTENTIAL PROBLEMS AND RESOLUTIONS
Issue 1:
WDS fails part way through the process, leaving the vehicle in a condition where it will not start.
Cause: Most failures are generally caused by the vehicle battery voltage being low, faulty WDS communications leads or poor connections at the vehicle’s J1962 data link connector (DLC).
Resolution:
Make sure vehicle battery is fully charged. Make sure that PTU is left on base station.
Page 6 of 15 Bulletin Number 1-186
Haven't started the car for a week. Now have an oil leak coming from the left rear side on the engine. Maybe a valve cover gasket.
So I've got a 2000 Jag convertible that looks great. Distinctive color, flawless paint, perfect top, nice interior. CA car w/ 75k. Starts but RP/yellow/now red. One short slow test drive. Didn't know I wouldn't be able to pull codes. Guesstimate on repairs (tensioners, maybe coils, minor stuff) is 4k. Paid too much so I'd be in for 8k. Hard to say if this is worth doing. Googled and see many similar cars listing for 15k.
This is an off-the-wall suggestion. Perhaps not relevant to this particular car... but.
In the old days, the Jag engine was pulled out and replaced with a Chevy crate motor and transmission. What would happen if you took it to a hot rod shop and yanked the whole thing out and installed a Ford crate motor? This was the Ford era, and the X350 XJ6 is a Ford motor, so it's not too much a butcher job. In the end, an X350 is still a mechanical beast. Find out what needs the ECM and ditch it. Of course in some locations, like California, this breaches the law, which then introduces option 2
Option 2: If you are looking forward to the day ICE are banned, do this. Upgrade to electric. There will come a time when the extraordinary aluminium body of the X350/358 will be recognised for the outstanding technology in the body, and the style will be super cool.
Sadly my 2004 XJ8 has reached the end of the road
