Wanted to give you all with XJ8/ XJR air suspension trouble a little tip to try if you are having similar symptoms.

My 2004 XJR front suspension recently dropped to the ground when it got really cold out (around 10 degrees). I got an air suspension fault message and a vehicle too low message (no kidding) the front was practically on the ground. I looked for leaks at the tank in the trunk and also looked for leaks at the top of the front shocks under the hood. I even unplugged the battery to try and isolate the droppage to 1 corner. When I plugged the battery back in and turned the key on I could hear a large hiss coming from the front passanger corner. I popped the hood and listened for a second-- air was leaking from the front passanger shock at the top where the CATS (computer active technology suspension) sensor plugs in. All I had to do was tighten that bolt a little (not even a quarter turn) and it stopped the leak. I also tightened the shock bolts a little as well as all of the bolts on the driver's side shock for good measure. The car is fine now! Hope this helps.

 

Please note-- After I unplugged the battery, I let it sit overnight in the cold. Please also note-- the rear shocks were fine and working the whole time.

 

you got lucky, line leak and not the compressor or shock failure. Hope you don't have to deal with either one for a long time. Thanks for sharing your information also.

 

Good info. Thanks. I have an 04 XJ8 and started getting the "Air Suspension Fault" error about a week ago when it got really cold her in the N.E (I live in PA). It has 53,000 miles on it and this is the first time I've gotten the warning. Fortunately the car has been driving fine and the warning goes away one the car sits for a few hours. I'm praying that my compressor isn't going bad.

 

I've got the same symptoms as carmat with my 05. Once the first below freezing night came though, I'd start the car, drive for less than a mile, and get the Air Suspension Fault message. If it (the temperature) warmed up a little throughout the day, the message would not come back until later at night when the temperature dropped, or the next morning. The car maintains ride height even overnight, with only minimal drop all around (no different than any other time of the year, when it displays no messages).
I have a feeling the compressor is on the way out, and is not putting out enough pressure to satisfy whatever sensor monitors its output.
I haven't had a chance to get it anywhere to have the codes pulled, but I plan to get that done soon.
Additionally, the previous owner mentioned this happening a couple times during the cold.. So, something in there may just not like the severe cold, so I need to start looking for a compressor...

 

I have had a similar problem with my 05, am at the shop right now getting the codes pulled.

 

My 04 XJR does it too! I think I got a C2303 Reservoir plausibility error. I'm down to a possibility of the Air suspension module, Preassure switch or a weak battery. Have any of you gotten a parking brake fault too?

 

thats almost always the air suspension compressor. And if youre buying the repair and its cold. Live with it, cause the air suspension looks for the reservoir to fill to the correct psi in a specified time period. If not it will kick on reservoir plausabilty error. Most air suspension issues as many note on here are from cold temps when, ahem....everything shrinks(seals etc pump efficiency goes down and small leaks develope that mysteriously disappear)

 

Yes I do sometimes get the parkbrake fault as well. It usually happens after I disconnect and re-connect the battery. It says to engage parkbrake-- sometimes it won't engage and that message will appear. If you just turn the car off and back on and try it a few times it will remedy itself (on mine anyway).

 

Better if it's the compressor rather than the shocks themselves-- they are a lot more expensive.

 

Thanks Nellerbeck. Your post led me directly to the problem on my '04 XJ8. I heard the hiss, and tightened the same connections. Seems to have solved the problem. Thanks for the informative post.

 

I think I will live with the suspension fault. It doesn't effect performance and I mainly drive the car in the summer. I do know you need to reset the parking brake if you pull the battery. It has only been an issue once. I guess theses are the characteristics of the car.

 

2004 -2009 XJR or XJ8 AIR SUSPENSION REPAIR,,, Note XJR uses the sport Suspension on this site...Air Suspension Part at the Dealer is $1500/wheel ... see this site below ... Remanufactured OEM for $399/wheel and they come with a LIFETIME warranty. Just ordered some and will try to update this after they have been installed... PS... cost to install is $329 here in Humble, TX.... Makes what would be a costly repair a LOT less painful.. Hope this helps someone if they need a new Air Suspension shock.
http://www.arnottindustries.com/part...20_pid136.html

 

Thank you Staylorcpl-- that is great info to have. I searched high and low about 3 months ago and could not find any aftermarket shocks for my 04 XJR. Thanks again

 

So far very satisfied. Cost $287 to R&R the two front shocks (included RE-alignment) Will return old shocks for $150 credit in deliver box with return UPS labels supplied. Steve

 

Is there a character in the VIN that tells if an XJR has the air suspension?

 

No but then all X350's have air suspension, well they did when they left the factory anyway!

 

I hope this isn't considered a drift from the topic, but I have a suspension issue on my '04 XJR, 47k miles. I may be just used to my '95 XJR (tighter). But... the '04 is much "floatier" (technical term) at low speeds, and will set up an unsettled side-to-side pitching motion when it hits road irregularities (bumps or holes) on one side at a time...
The car isgreat at high speeds, and on smooth roads, but this seems wrong... is it something correctible?

 

While the topic of CATS is up I can't seem to find in any of the discussions how to distinguish between a compressor and shock failure. I don't have any problems yet but will probably have to deal with it at some point as most owners do. Thanks- not trying to change the subject either.

 

Hello all,

I figured I would respond to this thread to provide some information about my experience. this past December my 04 XJR with 40K miles on it was totaled due to the CATS compressor problem during cold weather. Jaguar has known that 04, 05, and 06 have had more than there share of issues with the CATS system and compressor but of course made no corrective changes or even speak on the fact that it could lead to serious or even fatal accidents.
My warning light came on about 3 days before my accident. I called Jaguar to let them know that it has come on and explained the the car was not sitting low but I had noticed a slightly rougher ride. After a few minutes of driving the light would turn off and when at a stand still I could feel and see the front of the car rise. Jaguar told me to bring it in that weekend for a diagnosis.
The day of my accident, the light did not come on until I was on the highway and had been driving for about 15 minutes. Because Jaguar did not make it a big deal I continued on my drive home not thinking much about it. As I was taking an exit from the HOV lane headed home there was a huge dip in the highway in the middle of a right hand curve. I could feel the car almost bottom out and the back-end of the car bounced in the air twice. On the second bounce leading out of the turn the back-end kicked out and I did dukes of hazard jump over the embankment into the lanes on the opposite side (same travel direction) leading towards the exit. I was perfectly fine, (car not so much) and the police were called and the car was towed away.
The insurance company immediately deemed it totaled and did a complete tear down to discover what had happened. I explained to them the situation about the CATS warning and what the response from Jaguar had been. The insurance company came to the conclusion that there was a catastrophic failure of the rear right air bladder of the suspension system (because it had low pressure) which then caused all 4 sides to fail. Upon further investigation, I found on my own that there had been other major accidents caused by the air bladder or compressor system failing.
So the point of this rant is to warn you that although it is only an amber warning and Jaguar will not make a huge deal about it and just ask that you bring the car in. I would never drive my car if the compressor system is acting up even a little bit and especially during cold weather.

Thanks,
Rob