Hi everyone, so this is my issue. I received my 04 jaguar xj8 (Roxi) from my dad whom was the 2nd owner. The car has been garage kept till I got it from him 2 yrs ago. Since its been my daily driver. An excellent car in my opinion.Before I was able to drive it I had to replace the radiator which was easy. Since then its gotten all new front and rear tie rods, a arms upper and lower rear,, traction bar bushings, front stabilizer bushings, breaks and tires it also has gotten all new air shocks front and rear as well as a new compressor. Ignition coils and plugs, plus regular oil changes, new breaks and new battery. I've put about 40k miles on it myself. It has about 172k miles on it now. Throughout the last 2 years it would throw vehicle too low code, abs fault, gear box fault and restricted performance codes but they would fix themselves when i would turn the car off and restart it.Now to the issue was driving it the other day and it was fine I parked it and came out the next day and all but the driverside front shock were on the ground. I cannot figure out whats wrong I have checked all fuses and relays, all the lines to the air shocks, the compressor, the air tank in back, the valve block the connector to the ASCM( air suspension control module) in the back seat. I've even put an inline air valve in the trunk , by the valve block to try to raise the suspension with a different air compressor not connected to the vehicle, to no avail. I need to add that the compressor doesn't start when I start the car. The only way I can get it to run is to jump the relay.. Anybody have any ideas?What I should try next.I'm frustrated at my wits end. Thank u

 

Codes from a Jaguar specific code reader, that you already have, or need to acquire?

 

Without a code reader to see what the Air Suspension Module is doing, it's entirely guesswork.

 

You have a long and expensive road ahead of you.
Listen to the advice given above and post back with the results.
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The absolute best thing to do is to realize that the air system is sitting at about double its design lifetime, and order a set of coilover struts from Arnott. There are too many places in the air system that can encounter problems with age, mostly from water intrusion. The system has no facility for removing water that gets past the absolutely inadequate "dryer" in the compressor, and valves will rust and fail.

Get rid of the sir and install a completely passive set of struts with steel springs, then drive forever with no further worry.

 

Well thank you for the sound advice. I took and bought a set of coilovers for my car. I expect delivery in the next 5 to 7 days. I already have the car waiting for them.

 

Also have an 04 XJ8 and got Vehicle Too Low warning 2 days ago. Suspension in the front sinks when sitting for 2 days. Once I start the car the compressor will get the shocks up, sometimes it takes 2 starts to get them fully raised. Would the multiple starts indicate the issue is with the compressor and not the actual shocks?

 

If the suspension sinks so much within 2 days that you get the "vehicle too low" warning, then you definitely have a leak somewhere, and that could also be the reason why the compressor takes two starts to raise the car fully. Where that leak is, I can't say, there are multiple areas, such as the struts themselves, the air hose connection to the struts, or the tank and valve assembly in the trunk.

A car without leaks and good air struts sinks maybe 1-2 cm within some weeks, at least that's what my car does. Even after 4 weeks, it does not lower so much that I would get the "too low" warning.

As already stated above, the advise is to get a Jaguar specific code reader and see if the are some DTCs that can show what's wrong.

Best regards,

Thomas

 

Thanks, and agree there is a definitely a leak somewhere as the sink is very noticeable when it happens. I am taking it to my independent Jag tech next week who has the right readers to diagnose. Kind of a downer as I had the car a little under a year but I love it and knew the time was coming I would need to invest in the suspension. Just was trying to get ahead of what the diagnosis may be and go in with as much knowledge as possible

 

The reason it takes two starts is that once any air suspension fault is displayed, the electronics "give up" and stop trying to fix anything. This is to avoid having the compressor always running and burning it up. You need a code reader to see what the actual failure is, but even then you're looking at what may be some expensive guesswork. You most likely have a "reservoir plausibility error," which means the pressure in the reservoir is not coming up to expected levels within the expected time.

My advice every time someone asks about this is to ditch the air system and get a set of Arnott comfort coilovers. The air system is at least a decade beyond its design lifetime these days, so put steel springs under the car and forget about it. In my own case, the air system never worked correctly when I bought the car, I had to wait two or three minutes every morning for it to raise up, and I could only drive 15 minutes or so before getting an air suspension fault message. In 20 or 30 minutes it would be "Car too low" and the car would be on the bump stops and extremely harsh. Even when it wasn't down on the stops, the ride was not what I expected most of the time.

After installing the Arnotts, this became the absolutely most comfortable car I've ever owned. Four years later and I've never even had to think about anything with the suspension, and cross-country trips are great.

 

Thank you! This is what I was looking to understand in terms of the behavior. Sounds like I won't be able to isolate it to any one part without the proper code reader. I am not against converting to coilovers, my tech does that as well and that was one of my questions to him. I assume when you convert you have to do all 4 and not just the end that is sagging. Thanks for the feedback!

 

I've heard of people doing one end of the car at a time, but there will definitely be errors for the module from that, I think. Absolutely don't do one at a time, or one side.

 

Listen to wfooshee! I also fought the air suspension for a number of weeks and finally went to steel coils.
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thank you all for the advice. Realizing it will likely be an expensive fix but sort of knew it would come eventually. Will report back once I get the diagnosis for future reference.

 

Thank you all for the advice. I have some coilovers coming in the mail. I will update you all as to how that goes when im finished test driving it after the install.

 

The car may ride high after they are installed, but will settle after just a couple of days, so don't panic if you see 3-inch gaps over the tires to the fenders initially.

This was on first letting the car down after installing my Arnotts:


And this was after a 2.5-mile run to my office.

 

Lose the air suspension and life will be wonderful.

 

You specified Arnott comfort coil overs. Is that because it is the closest to the original ride?

What do you think about Arnot struts?

THANKS!

Merry Christmas!

 

Arnott has Comfort and Sport kits, being replacement for original struts in Comfort or Sport suspensions. The Jaguar Sport suspension has smaller air bladders which is effectively a stiffer spring, so the Arnott Sport struts duplicate that with a stiffer spring compared to the Comfort struts. XJRs, and cars that had the word "Sport" in their model name would have the Sport suspension originally. (That said, I really don't know about the word "Sport" being in a model name... I just got that tidbit from a web search.) Other differences in that suspension included anti-roll bar changes (or additions.)

Basically, the Comfort struts are what you want unless you're in an XJR. I can't say how they compare to the original air ride because I've never been in a car with air suspension working correctly, but I can say that the Arnott struts made my car extremely plush compared to the failing air system it had. I don't even have to slow down for the two speed bumps on the road into my neighborhood, it just absorbs them.