Hello,
I'm new to this forum having recently purchased a 2006 Super V8 with 126K miles from a car lot in Houston, Tx and driven it back 600 miles to Arkansas. It had a CEL with lean operation codes that turned out to be a disconnected PCV valve, and I was getting a "check pressure spare tire" message because the lot put in a spare from a 2004 XJ8 when I insisted I needed a spare for the trip home. Lately that message comes up only once when starting and does not continue to flash so I assume it has decided that I am not going to do anything about it.
I am getting a clunk in the front end on bumps which I assume may be bad bushings (a generous fellow Jag-Lovers lister who checked it out for me had them replace front a sway bar link which may or may not have been done correctly) and I have a vibration on acceleration that I assume is the exhaust vibrating which may need to be "normalized" according to directions in a downloaded X350 shop manual. I also feel a sort of rolling vibration on smooth roads at 70 with a period of about a half second that may be in the drive line - not terrible, just a little annoying.
Now to the real question - I get an occasional "air suspension fault" that will go away when parked overnight. The car lot mechanic told my JL friend he had replaced both front air struts and from the cleanliness of the studs and nuts and the greasy fingerprints in the engine compartment I assume that was true, so here's the question. Is there any way to have the car tell me what particular air suspension fault it is reporting? I have an UltraGauge on it, but it reports only engine trouble codes, set or pending, and not other body codes. I plan to get it up on our car club's 4 post lift soon, so what should I look for and plan to do when I get under there?
BTW, I bought this car for my wife after a year of searching for a 05 to 07 VDP and I absolutely love it. It has some door dings and dents and some driver's seat and arm rest leather rubs, but for the 7G I have in it so far it seems a fantastic car.

 

A lot of these after-market readers can't read all the codes Jaguar use, and a fair few relate to the air suspension system. Somewhere on this forum is a list of these codes.

Try the attached file. Most common for suspension is C2303 meaning that the air compressor is failing to charge the reservoir within the allowed time. This is usually because the compressor piston seal is worn out, but sometimes it's because there is a leak somewhere. Most times it is the compressor, as the piston seal is notoriously short-lived.

 

Thanks for that list - looks like a lot of things can trigger that message. Are there any DIY code readers that read Jaguar specific codes? Or is it a dealer visit to find out what triggered the message? (assuming it is still in memory somewhere).

The SV8 ride does seem harsher than I expected (being used to my 87 Series III XJ6 and 86 Daimler Double Six), but perhaps it is a difference between 15" wheels with tall side walls and 19" wheels with minimal side walls? Or perhaps an air suspension problem even when the message is not showing? Still it is an awsome ride.

 

Can't say if a market-place reader will read all the codes, but what I can tell you is that I, too, had an XJ Series 3, and the ride was like a Magic Carpet. Jaguar under Ford made the cars better but lost that ride refinement. Use of large diameter wheels with skinny wall tyres didn't help one little bit. I had 20" when I first bought the car, and it was awful, so I swapped to 18", which are a lot better, but nowhere near the old XJ ride. Just look at the aspect ratios - old XJ 205/70, compared to my 235/55 !!

The old balloon tyres took out a lot of the high frequency stuff coming off the road before it got to the suspension.

 

Yes, I tried to explain to my wife that those big chrome 19" wheels that she "absolutely loves" were likely a contributing factor to the seemingly harsher ride. One of our club members with an 05 XJ8 said he had to replace the front air shocks and the pump on his car, so I am at least a little ahead of the game because the car lot mechanic said he had replaced the front air shocks on this one. The club member also said his would "let down" when he had pump trouble, but I haven't had that yet that I am aware of.

Driving to the British Iron club meeting tonight I got the "air suspension fault", but driving home afterward there was none. Interesting that none of the air suspension faults on the code list light the MIL, but many of the DSC faults do. Must be a Big Brother mandate. Lots to learn about our new cat.

 

When I still had air suspension, mine would ride unusually hard and harsh after longer runs on the highway. It eventually completely failed and I ended up swapping out everything for coils.

 

I should not speak too soon, but my 2006 SV8 rides smoother than any of my previous Jags (including my XJ-40 tank). When the system is working correctly, it is as smooth as silk. With the added 5", the long wheel base is like no other car. When you get it all sorted out you'll see/feel it. The 19" wheels are not that big of factor compared to the 20's. But tire selection is a HUGE factor. My pirelli P7's are smooth and quiet compared to the cheap tires that were on it when purchased. At one time I thought that I would not find a car that was as smooth as a huge Lincoln Town Car, until I drove a SV8. Now I have a smooth quiet ride, that will out handle those giant Lincolns. And then theres the supercharger !! Thats another story. You may have a couple of issues noted on the forum.
1. What shocks were installed (sport or comfort) or the correct ones.
2. Is the CATS system working correctly (could be stuck in harsh performance mode)
3. What tires are on it. (my XJ-40 was great with Michelins, but not my X308 or X350)
Start with the simple things.
And yes the series III has been known to give a great smooth ride.
Let us know what you find, and the forum will take you to the moon.

 

I haven't been under it yet to see what shocks were used and don't know about CATS other than the 5 my wife has (please educate me). The tires are a mixed bag with Michelin Pilot Sport A/S 3, P255/40ZR19 100Y dated 2415 on the rear and on the front a Goodyear Eagle F1 and a Pirelli Pzero, both P255/40R19, with dates in 2011 and 2012


Hope I don't have to go that route for awhile. Seems it is riding OK except for a clunk in the front on bumps and a slight exhaust rattle under torque acceleration. Need to get it on the club's lift to see what the clunk is and perhaps adjust the exhaust.

 

Phil Warner,
I had the same problem with my 04 XJ8, checked everything, and they all checked out fine. Still get the "Air Suspension Fault" once in a while, but it normally goes away after driving for a while. When I stop, then start it up, the code is gone. Funny thing is that the ride is the same with the code on or off. As far as the knocking noise, check the running light connector. Mine came loose and was knocking against the front frame rail. It was hard to see because of the underbody panels, but it was easier and less costly to repair than replacing bushings. Also, replaced all tires when they were due, with Pirelli P3"s and the ride is substantially better even with an 18" and low profile aspect ratio tire. Thanks to all who have replied on this forum, what a great source of wisdom for all of us needing help.

 

Just bear in mind when replying to threads on the forum to look at the date of the last post.

 

- Suggest check your ride height (tape measure ctr of wheel to fender lip) and check against specs

- Ride height wrong can trigger warning, plus rough ride

- If all is well mechanically, may need to reset ride height. My $200 foxwell scanner can't do ride height reset, but reads rest of codes OK. You may want to get a half decent scanner

- Replace front tires with AS3's, assuming rear AS3's are not worn out

- Note that suspension bushings/joints on these cars are infamously short lived, and your front tires might have been ruined by bad alignment. Check it first. Camber can't be set if ride height is off by much

- Rear suspension ditto, and rear lower control arms may be rattling too (vs exhaust)

- Spare tire TPS is bad

Welcome to the old Jag hobby...

 

Wow!
I totally forgot I made this guide. I'm glad to see so many people found it useful. I probably wouldn't bae able to answer too many questions about this job anymore as the good'ole Jag has "crossed over the rainbow" after 8 years and almost 160K additional miles (I got it with 40k) of mostly smooth sailing. I'm older now, with a mini-van as main mode of transportation (kids will do that to you.., but I do have plenty of good memories with the "cat". My head still turns whenever I see similar VPD on the roads... Ahh, good'ole times...

 

@Mark in Maine How do I know if my CATS stuck in harsh performance mode? How can I solve this? Thanks mate

 

be sure to check the obvious obvious....tire air pressure.. i drove our XJ close to 1000 miles home and didn't realize the tire pressure was all over the map...worst tire was only 20 pounds. Also, non-matching tires can make a car ride harsher.