Hey guys, I've been bragging about you and now I would like to ask you for backup.

There is an owner with his '97 XK8 at a Jaguar dealership. His car lost an instrument cluster, and a susequent used replacement failed almost immediately. The other unknown variable is that he has previouslyinstalled an aftermarket radio and power amp. He SWEARS that he did not connect the vehicle speed signal (blue/ white) output wire from the instrument cluster, which is the only CAN network interface I could reasonably suspect. There are alot more specific details to share, I'd rather ask you to join in the discussion than to reprint it all here from the beginning. Anybody care to lend a hand?

By my count, there are four of you who are likely to have alot more CAN network diagnostic experience than I, and I don't have the car to troubleshoot. I'm just trying to learn something, and help a guy out who is stuck. Can weconvene a shop meeting?

Andrew Bernstein

 

FJT and _genius, you guys got a minute?

 

sure.... have you checked the can network for it's proper resistance? or at the DLC shud be 60 ohms and at the IPK 120ohms
if ok then somthing may be shorting out.. or open circuit.. all the input must be checked..

 

Thanks _g,

See, you're already over my head and I don't have the car. If you want to work the puzzle a bit, I can redirect you to were the story is played out, or send the posts to you privately. I don't want to post someone else's website address here. I guess it wouldn't hurt if I cut and pasted the info. What works for you?

 

what ever is easier

 

you can PM me

 

_g, you've got mail

 

hey i just read the whole thing.. it's definitly not the SCLM because it is on the SCP network which goes in the IPK.. your idea of disconnecting all aftermarket crap is a good one.. and go from there. Also need to see codes from a dealer..
anything on a SCP network that is shorted together or to ground or to power.. just takes the system down and never the IPK . just all interior stuff doesnt work and SCLM . also with new IPK in wud be good to get a measurement of CAN network with everything plugged in.. but that seems hard to get..May be awiring issue caused by incorrect installation.or just acoincedence. definitly is the CAN network failling. ask him to measure the dead IPK at the two pins for CAN there is a resistor in there.. and it shud be 120 ohms.

 

and what does he mean by blown? fuse blown .. or just IPK nothing visually working ? and no start?

 

thanks _g,

I caught most of that, thanks for straightening me out. I'll try getting codes to research. What would testing the IPK resistor reveal...unless the pack is really still good, and it's just an IPK connection problem?

I guess one other question would be: assuming you have seen IPK death causing CAN failures, and I have read of twoothers onearly XK8, have you found an external cause for the IPK failure? I think by "coincidence", you just meant that the IPK failure was unusual but not unheard of, and the replacement was just a used piece of crap that failed right away.

 

He's got symptoms listed down towards the end of the thread. I asked about that too. Do you see all of the posts?

 

wud reveal thatCAN may still be up just rest of the circuitry is down and causing fake CAN codes... and have seen IPK go just fuse blows and there toast.. if he took a old xj pack .. the early ones did have problems.. for shorting out.. causing weird light to come up.

 

Owner statement:

"As far as what "blows"--I should have been more clear. The tranny disables, and I get ERR in the temp unit, engine fault, and transmission fault on the computer, the check eng light, and the speed, tach don't work. ...I checked the codes with a scanner, and they are generic CAN communication error codes. Very nonspecific. The dealer did a full check, and was the one that claimed I needed to replace the cluster.

Good thought as well on the fuse, but it is 5A as it's supposed to be. I shouldn't have used the word "blown" for the cluster."

My addendum: those are the same faults I had on a '97 coupe with a blown IPK circuit fuse...and the fuse never failed again that I know of. Engine start and run unaffected.

 

The IPK is the translator for the CAN and SCP networks. Just throwing that out there as I have no idea about the rest of the problem....lol.

Checking the resistance lets you know if there is an open in the network. I personally prefer to check voltage. CAN should be 2.3 volts on one side and 2.7 on the other. Roughly. If not, bad. SCP I forget, but should be close to 5 on one side and close to 0 on the other side....testing to ground of course. If you have 2.5 on the SCP then it is bad. Start unplugging things one at a time until the voltage is normal...then you found fault.

Definitly start by unplugging anything non factory as Genius suggested....sorry for getting in this late...lol

 

_g,

So first and foremost, you agree that disconnecting the junk is a good idea, although the problem likely has nothing to do with the junk. The secondIPK might have been junk too, and codes are required to further evaluate... and test the suspect IPK(s) resistance to verify that itis toast. Am I reading you correctly?

 

He could also have gotten an IPK with different VCATS number. Just saying.

 

yes and FJT is correct too.

 

lots of variables..

 

FJT are you having problems with the disc 112?

 

None...put it up to patch 4 and not had a lockup yet......I like it.
Did you get the email of the pics....lol.