OK, here's the deal. On every engine start, the "DSC system fault" warning flashes by in less than a second, then disappears and does not return at any other time, especially not while driving. However, I'm led to believe by the driver's handbook that the little red light on the console DSC button should be flashing to indicate proper operation of the system. This does not happen. It lights up fine when you depress the button to turn the system off, so no bulb/fuse issue.

The car runs flawlessly (said in a whisper, with due reverence to the Jaguar gods), there is no untoward braking behavior, at least as far as I have been able to ascertain, no other warnings, especially nothing to do with ABS, no (other) electrical gremlins at work.

The battery gets a full recharge from the CTEK every one to two weeks for as long as the cat sits in it's warm lair, waiting patiently for those all-too-rare, nice, dry winter days.

The gurus at the dealer had a look, found code U1135, which has to do with "Invalid or Missing Data for Ignition Switch / Starter", told me further investigation would probably be "involved" - which in my mind translates as "costly" - patted me on the back and told me not to worry.

I'm fine with ignoring the warning itself, however, DSC sounds like a "good thing" (TM) and I'd like to feel confident it's actually working. Is there any way to confirm this? Should I take any further action, or just chill, drive and sleep soundly?

Forgive me if this topic has already been battered to death. I actually did check, and I'm kinda thinking a wheel speed sensor issue might be going on. Sound reasonable? Any other thoughts?

TIA!

 

Your battery may be aging, causing the voltage to dip too low when the starter is engaged. This can erroneous messages to be stored.
The DSC is working, I believe. You can test it by accelerating briskly from a stop on a gravel surface and see if there is a significant difference in wheelspin with the DSC engaged vs. off. Considering where you are, you might find some ice or snow instead.

 

DSC only FLASHES when it is operating not when it's sitting idle waiting to do its job.


The previous post by RJ237 is a good suggestion as when you do get wheelspin you should THEN see the DSC light on the dash blink rapidly for as long as it's compensating for any instability caused by the wheelspin.

 

JagNoir, according to the JTIS the code you posted for a 2003 XK8. U1135, relates not to the DSC (stability control) but rather to the driver's seat control module and/or the driver's door control module.

From your description of the momentary flashing of the DSC light but NO reported code I'd bet that's a circuit test and not a true fault since it occurs ONLY at start-up. As for the U1135 code have you ever had trouble with either the seat controls, the door controls, or the memory settings for 2 different drivers that are mounted on the driver's door?

 

I got my take on the U1135 code from Gus' post here, but I did also see posts mentioning the control module thing. Just didn't think it was relevant, because all seat/door/memory controls work as expected. Even the folding/dipping mirrors work, although it took me months to realize the car even had those features...

Right when I got the car about a year ago, I did have the "usual" woes with the headrest cables (both) coming unstuck, as in motor sound but no movement, but that was fixed and now I basically leave the headrest controls alone, just to be on the safe side. But they do work.

I will now devote my efforts to making the wheels spin and the DSC light flash. Sounds like fun!

Thanks for clarifying things.

 

Hi.


Here is an extract from JTIS for your code:

 

Ah, so allegedly the DSCM is not obtaining valid data on ignition status. As long as everything works, I can live with that. In any case, totally unrelated to the DSC warning.
Getting the JTIS to work (on Windows7) is on my to-do list for today - or rather, getting the links to the technical files (pdfs, I believe) to work from within JTIS. Looks like then I will be able to interpret my own codes
Mange tak

 

I was getting this same flash of this same message...
but now it's on permanently and accompanied by the amber 'ABS' symbol lit up.
I've cleaned the sensors and my battery shows 12.2v with ignition off.
Should I check the voltage when starting up? What would be a normal dip in voltage?
thanks
Steve

 

12.2 is very low.

 

JagV8 is correct as 12.2 volts with everything off is way too low. A fully charged battery in good shape should register 12.8v - 12.95v. The difference may not seem like much but consider that reading is with everything turned off (except for the always on modules that use a trickle).

Give your battery a solid 12 hr. +/- trickle charge (not a fast boost charge) and then check it wait a few hours and check it again. A good battery shouldn't lose any appreciable charge even if left overnight.


A full blown battery test puts a heavy load on a battery of several hundred amps for a very short duration (like a starter motor doing it's job)and then tests to see how long it takes for the battery to bounce back. If it takes more then a couple of minutes it probably has a bad or dinghy cell.

 

I'll do this test today. I've just lost cruise control and the engine management light has come on.
Many thanks

 

Just an update on this old issue. A new battery later and the DSC warning has not shown up once.

I guess there really is a reason battery testing/replacement is the single most common suggestion around here. Thanks to all of you who keep insisting.

 

Thanks for posting the resolution.

I've added RESOLVED to your thread title to help any future battery disbelievers!

Graham