Originally Posted by michaelh

Jon, From what I've seen, the caps in the 97 and 98 are the same: - made by Nichicon, and have the same values and type #s. Whether Nichicon was a victim of the 'bad cap' debâcle( see https://www.badcaps.net/ ) or there's something intrinsically different about the '97 ECM, I don't know.

Either way, electrolytic caps are not forever as their characteristics and efficiency degrade over time. A visual inspection may not show any clues, or they can fail spectacularly, as in greenforest56's case (long):
https://www.jaguarforums.com/forum/x...4/#post1776440



The ECM is, as Mad Hatter describes, under the cover in your passenger side false bulkhead. Here's ASI's description for its removal:
https://www.autoecu.com/jaguar-xk8-e...-instructions/

You may find (as I did) that the retaining screws are 'tamperproof' rather than torx, and that once you have the cover removed, you need to first pull the TCM out of the way.

There are seven caps that should be replaced:- one of which is hiding under the daughter pcb.
I posted the part #s here:
https://www.jaguarforums.com/forum/x...6/#post1806456
Cost is ~$6.

I can't promise that this will solve your issue, but it's good PM for the early ECM units.

Originally Posted by Mad Hatter

It has been mentally what feels like ages since I had to deal with this so my memory is a little bit fuzzy, but I remember getting this Christmas tree effect of errors a few times after disconnecting and reconnecting the ABS module.
I can't remember exactly what I did to fix it, but I think it involved removing the abs electrical connector and reinstalling it, and then removing the battery terminals and letting the car sit in timeout overnight before reconnecting.
I wasn't convinced then, nor am I convinced now, that these Christmas tree errors are always more serious than just the car remembering that it was unable to communicate with the module for a brief period of time and telling you all about it.
Helping it forget about its troubles might help you forget about yours.

I also had to replace the battery in the car 3 different times through the course of troubleshooting my errors to find a battery that hasn't given me Christmas light error codes.

If the problem persists after checking connections and letting the car reboot, then maybe I would heed the warnings and start double checking that the soldering work you did to the power pins was successful, and that the ECU is undamaged.
The ECU can be found in the passenger side of the engine bay mirrored where the brake booster would be on the drivers side. It is a grey box with tons of wires coming out of it. The transmission controller is sitting right in front of it and might need to be removed to get enough room to remove the ECU. It is a 5 minute job with just a couple torx bolts holding the cover on the compartment.




I agree completely. A lot of people are going to blame it on electronics making the cars more complicated and thus more to fix, but in reality what has happened is that the companies are installing the absolute cheapest parts possible in the electronics that not only fail prematurely due to shoddy PCB design, but also have shelf lives that ensure the cars become nuisances to keep around longer for more than 10-15 years or so. We are just buying cheaply engineered cars because it is more profitable for the company.

Originally Posted by crbass

Exactly the problem. He's going beyond repairing someone's module to providing modules, and he does not appear to understand the software (and/or maybe the hardware) issues...

Also a tad disorganized?

Originally Posted by oldjaglover

Thanks. I decided to bite the bullet and take it to a very reputable Jag shop locally. They were closed on Monday.... So, I drove around for several hours hoping some of the lights might go off. Not a chance. I had my son clear the idiotic P1637 code before I left, but it came back on instantly. Car drove and ran fine....also braked fine. This AM I called the local Jag specialist shop....and they first suggested sending out the ABS module for "rebuild". I told them I had already R&R'd the module and had it re-soldered. Silence. She asked what my code was, and I told her it was P1637. Her shop foreman looked it up and said IT DOESN'T EXIST! WTH?? She then said they have a $20,000+ analyzer that is better than what the local dealers have, and that they can find anything if its there. But, they didn't recognize a P1637 code that is so common it should come with a can of beer? Anyway, I made an appointment for NEXT Thursday to get it in and be checked out. Hopefully, driving it for another 50-100 miles might help.

SO....should I disconnect the battery in between these drives?

Originally Posted by oldjaglover

That "autoECU.com" link gives me a "not found" message.

I do think it's worth a look, because nothing else is working to resolve it.

Originally Posted by michaelh

+1
A $20K analyser isn't much use if they can't even translate a Jaguar P1637. This information is not exactly secret.

Originally Posted by Jon89

Possibly because like the majority of Jaguar dealerships in the USA they have abandoned any support of the pre-Tata era vehicles....

Originally Posted by Jon89

Au contraire, the better indie shops in our area are far more competent than the local Jaguar dealership is regarding the pre-Tata era vehicles....

Originally Posted by michaelh

Perhaps you spoke to the wrong person and they're OK, perhaps not. You may end up not much further along but $$$ lighter, though.

Originally Posted by oldjaglover

Possibly. They rescheduled my appointment, which will give me a few more days to figure this out.

My latest update on the situation: Quick update. After leaving the battery disconnected overnight from a NON-CEL start yesterday, I hooked up and started the car to put it in the garage. Easy start, NO CEL, ABS light flashed and then stayed on, all other warnings flashing, did not drive it on the road, and NO BEEPING WHEN I REMOVED THE KEY. So, it sits awaiting my attention.

Originally Posted by BobRoy

You are local for me. I have a Jaguar specific code reader that we might be able to get the C codes and give us a little bit more information. I also have a 97xk8 donor car with the ABS module intact. If the VCATS match you can try it to see if the module is your problem.

I sent you a PM. Let me knowif you would like my help.

Bob

Originally Posted by xalty

ABS modules that have been sitting outside for a while go back to virgin state and need IDS to pair

Originally Posted by Jon89

Your car will definitely remain healthier if you will get it out and drive it considerably more than 200 miles in 4 years. Have you had to replace your fuel pump yet? Sitting around unused for months or years at a time absolutely kills them....