Hi. I'm hoping someone can offer some advice to my current problem.
My 2005 XK8 (28k) has a permanent 'suspension fault' amber warning and drives extremely hard. Jaguar main dealer today diagnosed the ACC module as faulty despite the system working fine throughout the 2 weeks that the warning has been active! This ACC was replaced 15 months ago (under warranty as part of the Main dealer purchase) & I am currently arguing my case that I shouldn't have to pay the £600 bill considering I have only done 6k miles. This is on-going.
My question here however is have any of you ever heard of such a fault causing the suspension to go offline? I fail to see the relation but Jaguar are adamant that their diagnostics can't be wrong.
Prior to the suspension fault warning, I had intermittent DSC & check rear lights warnings. I cleaned all the speed sensors and was planning to look at the brake sensor when the suspension fault came on.
I have read past posts here but I can see nothing relating to these two areas together. Any ideas at all or should I just trust Jaguar & put it down to typical strange Jag electrics?
Many thanks in advance.

 

Welcome to the forum, you should stop by our new members area and introduce yourself.

You really need to get the fault codes read, without codes is kind of like shooting in the dark.

I've moved your post from the X350 XJ section to the XK8/XKR section.

 

My apologies for the mistake, I will be more careful in future.
I have just posted an intro having realised that I didn't do it when I first joined.
Reference the codes, is this something that I can ask Jaguar for or would they not want to share such info? I have been looking recently at purchasing a code reader (with Jaguar add-on) but with so many choices, I want to be sure of a solid, reliable (not to mention useful) tool.
I am speaking to them again tomorrow so I will ask the question at least. If I have any luck, I will post them here. Thanks

 

No problem!

You will need the codes read by a Jaguar dealer or specialist, a basic code reader won't see the B, C or U codes, only the P codes.

The DSC and CATS should show some C codes, the rear lights some B codes.

There is no reason why the dealer shouldn't tell you what the actual codes were. Unless they can't read them themselves....

 

I can't quite decide whether that is arrogance or stupidity!

Graham

 

Maybe simply because it was five minutes to closing time?

 

+1 what Cambo said, it will be a guessing game to try and figure out what the suspension problem is without them.

To your original question, the Active Cruise Control and the Active Damping have absolutely nothing to do with each other, they are not even on the same communication network.

Easiest way to test for a faulty ACC module is to set the cruise control. Does it function, including the distance keeping feature? If it does, then the module is fine. The first thing that happens when there is an ACC fault is you will get a message about the fault and then a second saying Cruise Disabled.

The active damping in these cars is pretty simple, if you had the fault code, it shouldn't be too difficult to find the problem.

 

Excellent, thank you.


This dealer has been great to date; really top class service but it goes to show that it's worth asking the question, especially when you're talking about a fair amount of money here!


The ACC was working fine when delivering the car to the dealer hence my worry. I have been reading a lot on here about a pinched cable under the seat in relation to the suspension failure so perhaps that's another port of call.
Getting the fault code comes first though so with luck I will post that tomorrow & see if any of you guys can shed some light.

 

Result.


Seems that I was right in it being an 'end of the day' mistake. Just received a call from them & it seems that the guy quoted the wrong module to me. It's the Adaptive Damping Module that has gone which now makes a whole lot of sense!
New part in, being installed today, pick up the car tonight; can't wait.


Thanks to all previous comments & help.

 

Quick update if anyone is interested: Top class work completed by dealer & suspension now sound.
Within the day however, the intermittent 'check rear lights' problem was back (knocking off the cruise in the process). Quick call to dealer & they advised me popping back for a check. Did that today & half hour in the workshop (whilst I drooled over a £75k XKR) & they found a brake bulb working but very loose in its metal body. They replaced both sides & sent me on my way with no charge.... what service!
Only hope that time shows that this was the problem all along! If it is, then it goes to show that sometimes it can be too easy to ignore the simplest of solutions.
Thought I'd post this in the hope that it might help someone; worth checking.

 

Glad it's been sorted out!

 

Hi All, Not sure whether my problem is similar to this members issue here but my dash display has indicated "Suspension Fault". This has occurred a couple of times now and I have the "DSC" indicated every time I start the car since I purchased it 6 years ago. The "DSC" indication has had no relevance to the running of the car, but obviously the "Suspension Fault" light is of concern. Having CATS on my XK8 I took a look at the sensors on top of the suspension parts and blew air into them and also on the top of the mount. Switching on the engine, it cleared the fault. However, In the past two weeks the fault has occurred only twice and both times I removed the sensor and blew into them. Anyone got any ideas what the issue could be? How do I tell if one of the sensors are faulty, which one it I likely to be?

 

Doug,

Have you been losing cruise control too? Is ABS lit?

Which sensor do you refer too? Wheel speed sensor would in my experience cause the cc, abs to flag too.

John

 

 

Read this post, which is a good description of how to fault find the cats suspension:-

https://www.jaguarforums.com/forum/x...7/#post1882621

 

This is not really a "sensor". The shock is active, to the extent that the rebound (as opposed to compression) can be controlled by current/voltage being applied to the top by the control module. There is no "sensor" to replace. If the shock is bad, it need to be replaced, and is a bit pricey.

To my knowledge, when the system fails, the shocks all default to the hard rebound setting, making the ride less comfortable. There is a way to disconnect the system in the trunk and let the shocks go back to soft rebound (all the time) while you figure things out.

From memory, it seems like the electronic board for the CATS controller can sort of fail to properly drive the shocks. You might have to do research on this forum. Another possibility is reach out to a rebuilding service and see if they have the expertise for this. Folks mention ASI all the time (no direct experience myself).

Should have probably started with the obvious: have the (Jaguar proprietary) codes read to see what the controller's diagnostic is. Without that, you are guessing, blindly throwing money at the problem.

Best of luck, keep us posted.

 

Thanks fmertz, interesting slant on the issue. However, how do you explain that by pulling off the ‘wired caps’ on top of the shockers and blowing air into them and then putting them back cures the problem temporarily?

 

If you think this messing with the connector activity counts as valid diagnostic, then feel free to pursue it. Use a spray contact cleaner, and maybe bend the pins a small bit to promote better contact. See if you can use sand paper to freshen up the contacts. Also, follow the wiring as much as you can to see if there is any type of damage, frayed insulation, etc. All these are going to be near zero dollar activities, so they are good to get out of the way. There have been report of these modules possibly being affected by these tests, so be sure to disconnect the battery to avoid damage to the circuit board. If you do disconnect the battery, have the radio code ready if you are in the UK, and do a quick read on the window reset procedure.

Also, re-reading your original question, you might have to fix whatever ABS/DSC problem you already have first. This dynamic suspension system is likely to require input from the ABS/DSC system over the data bus to properly operate. If these messages are missing, you would likely have a fault from the CATS.