I wonder if anybody could throw some light on the cause of this please.

For some time now the warning Air Suspension Fault has appeared on my dash usually after a few miles of driving. nothing seems to change in the handling.
But just recently I have been carrying passengers and luggage and the Air Suspension Fault never shows itself !! - as soon as I am on my own driving again the Fault re-appears !!
Any suggestions please ??

Best wishes

 

You'll have to get a tool that can read codes from the Air Suspension Module electronically. The codes will tell you why it threw the alert onto the dash. You cannot troubleshoot the system without knowing those codes.

 

Thank you Wfooshee for your immediate reaction, I have more info to impart.

Cheers

 

Had same problrm recently.
Light came on after 10 minuites.

Two probable causes
1.Malfunction of compressor
2. Leak which makes compressor work more.

Had 1. Solved with either piston ring replacement or new compressor. If you buy new one only get original. Wabco by arnott.I Iearned the hard way.

Good luck

 

Thank you

 

Don't start changing anything until you run the codes. The air suspension is complicated and very failure prone. There are dozens of possible fault codes.
What I would do is start thinking when to replace the air setup with steel springs.
Can you DIY any repairs?
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I made deliberate decision not to do coil spring conversion.
I really enjoy the air suspension.
Its one of the features of the car which in my opinion sets it apart from others.
Yes it can go wrong like any other thing with an 18 year old car but when shes flying with air suspension shes a beautiful ride.

 

He's right, though. Without reading the codes from the air suspension module, you're just guessing about what needs to be fixed. The system is very sensitive to water intrusion, and the fact that the dryer is deep inside the compressor, as opposed to an external serviceable part, is a serious design flaw in not just Jaguar's, but all automotive air suspension systems. They all put the dryer deep inside the compressor.

Leaks can happen about 348 places throughout the system. Level sensors can go bad, electrical connectors can go wonky, and of course compressors wear out.

Aside from reading the codes and knowing specifically where the error conditions are, water getting into the system stays in the system, there's no way to release it. The valves in the valve body, and the vent valve in the compressor, will all rust and become inoperable. Water will collect in the reservoir, which has no release valve or other draining facility, and will collect in the struts, and continue to be distributed throughout the system as the air is moved through the system.

I have no interest in disassembling the compressor at least once a year to service the dryer desiccant, and still probably have to replace the valve body and struts every 5 to 8 years, simply because I live in Florida and can't keep water out of the system because of the regular high humidity here.

I have no issues at all with the ride quality of my Arnott coilovers, although I fully admit to speaking from ignorance about a working air suspension system; I've never been in one so I can't compare. All I can say is that with the value of the cars being what it is, spending at least a quarter of that to keep the air system is just not brilliant economics. A working air suspension system adds no value to the car over a good coilover system. For myself, I would actually prefer a car that has been converted from air to steel. were I currently shopping for one; I would know that I have no huge maintenance headaches coming up withing a few months or years.

 

clue:

"after a few miles of driving"

Possible piston ring needs replacing on compressor
but confirm the code first.

 

OK but you did not answer the most important question?
Can you DIY this work? Do you have and know how to operate the Jaguar SDD system? It is mandatory if your working on the air suspension. There are dozens of codes and you need to see them all to get the system operating correctly. Plus SDD allows you to operate and test things.

I ask because I have many,many hours repairing and troubleshooting the Jaguar XJ air suspension. I have rebuilt air compressors (Do you know Bagpipingandy yet??) and rejuvenated desiccant beads by cooking them in an oven. Replaced air struts on all 4 corners and of course as mentioned above don't forget about the valve block. Are you familiar with what's called "The Olive". If not again you have a LOT of learning to do!

Plus one of the main problems now is getting working air struts. Arnott's use to offer a rebuild service and would buy back you old air struts if you went the steel spring route. They no longer offer that for the Jaguar XJ. The factory is hit or miss with their supply and of course get your check book out if you have not priced air struts. So the system is almost impossible to keep operational.

Now I do admire your goal and I have driven an XJ back to back with air springs and steel strings. There is zero doubt that the air springs ride better for the most part. What is not mentioned is why the two type's of springs ride so different? The air springs do not transmit all the vibrations up and down strut like the steel coil springs do (Resonances). These resonances are what gives you "Road Feel". Some like that others think it should not be there. Instead the air absorbs all that giving a much smoother ride. This feeling also leads to what some people call a "floaty" or disconnected from the road type of ride and not well controlled in the corners but that is incorrect. The air is softer but the car corners just as well so it really is the best of two worlds.

But the real world implementation of air suspensions in general have just been a mess! It's not just Jaguar either I have worked on S-class MB they end up in the same spot. Car all jacked up and thousands of dollars to "maybe" repair it. I don't think you can count on factory tech's as they don't seem to be able to fix it any better than us shade tree guys!

Here are some places you need to get familiar with and do ask a LOT of questions and search as we have hundreds of threads with conflicting advice.

Air compressor expert and maker of the compressor re-ring kit Bagpipingandy.

Air compressor repairs

Next is Arnott's probably the biggest company in the aftermarket air suspension game.

Air Suspension Parts

I just looked at Arnott's and currently they do list the air struts and air compressors and valve blocks but no pricing? So maybe you can get parts?

They offer a real well done steel spring kit that also includes a bypass that takes care of the error codes so no lights on the dash. Again I have installed this kit and it works great. It's so nice to come out to the car and not see one end or one corner or the entire car slumped down on the suspension stops.

Finally there is a lot of documentation out and you need a copy of ALL of it!!
Here are few things and I have a large 12MB dealer training document that is too big to upload to the list.
Can you post your car info too? The system changed some as the years went on.
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There has been a lot of good recommendations and documentation provided, but here's my experience with an issue similar to yours.
I had the same problem where the "Air Suspension Fault" will appear almost every time I drive the car and then it goes away after the car sits over night or for an extended period of time. I did not do anything about it until I bought an OBDII scanner that can read the Jaguar specific codes. Initially, I had two air suspension related codes, so I reset them and waited for new codes to trigger. After a month or so, only the C2303 came back. I ordered and replaced the Bagpipingandy kit. I did not do anything with the desiccant beads as I am in a good climate and hoped that they didn't need to be refreshed, and it looks like I got lucky. I haven't seen the Air Suspension Fault message since the kit was installed, 10 months ago.

Fixing or replacing the compressor will eliminate the Suspension Fault, but most likely the fault was the result of another underlying issue, such as an air leak that is causing the compressor to run frequently, and when it needed repair, it was triggering the suspension fault message. Once it is fixed, it may not trigger the message anymore, or at least until the compressor goes bad again, so if you end up fixing or replacing the compressor, you should monitor the hight of the car and the frequency the compressor is running. If it is running every morning, it is most likely because of a leak. I am in this situation right now, where the compressor will run every morning or after the car has been parked for few hours. The car was dropping a noticeable amount during the winter, but not as much now, during the summer, which indicates there is a leak in the system. In cold weather rubber will not come together to seal a leak as good as it would in warm weather.

 

Monstrous assumption there!!!! It fixed it for you, but you apparently didn't have any other issues other than a weak compressor. A compressor repair does nothing for bad valves in the valve body, leaks at any of the air line connectors, or even damaged strut bags. And not even looking at the desiccant while the compressor is already in your hand is simply not brilliant. "Good climate" or not, there is water in the air, and the system has no way to remove the water if it gets past the compressor's dryer.

 

Oh, let me know how you feel. Monstrous is a very strong word here. Sure, maybe I should’ve rephrased my statement to "if fixing or replacing the compressor eliminates the Suspension Fault".

Regardless, in the context of the issue that is being described and if the code is C2303, more than likely, fixing the compressor will eliminate the Suspension Fault message.

 

You can get the Arnott struts reasonably priced at Rock auto.

I had the same code and fixed compressor and code is gone still 4 months later.

At the end of the day one has to decide if your keeping for the long run and what is your budget.
Im not selling this car and love air suspension ride.
Best car ive ever had....and probably will have

 

Well, you're right, when specifically addressing the C2303 fault. I read your post as "fixing the compressor fixes any fault," which is not what you said. I missed where you specifically addressed the C2303.

We still don't know what the OP's fault code is.

 

Oh I STILL have night mares about those C2303 "reservoir plausibility" errors!

Also remember that code can be caused by a number of things and generally has nothing to do with the air reservoir which is under the spare tire in the trunk. It's a small beer keg looking device. I have seen bad air struts, leaking air lines and leaking valve blocks as well as a weak compressor set this exact code. So yes it "could" be the compressor and at this late date regardless of what you do consider just rebuilding the pump with Andy's ring kit anyway.

Keep posting as you can see there is a lot of experience on this forum.
Good luck with the air suspension too.
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I don't know what the fault code was but I have had ride height issues. I rebuilt the compressor years ago and it appears may need to do so again. I had it check out at a good independent shop in Monterey California and Joe determined that there was a faulty ride height sensor. I'd had the yellow light "air suspension fault" and that seemed to cure it. Now a month or so later the compressor is kicking on all the time and I'm getting both the red light( vehicle height too low) and the yellow saying air suspension fault.

I'll do the rebuild again and then if that doesn't solve it take it back and have them trace the issue.

 

The the cylinder is available, as well as the ring, to restore the compression