Hi Guys

I own a 2003 XJ8 4.2SE, which I bought as an ex-dealer-demo car with 900 miles on the clock. It currently has 180k miles on the clock and has been a truly awesome car, still every bit as good as when I first got it.

The only chronic problem is the intermittent flashing up of the "air suspension fault" warning light. It has been into the dealer numerous times, and they say that there is nothing that they can do: the compressor gets the pressure to the requisite level in in three minutes, so it's fine; it is a known fault; just switch the car off and then on; don't be such a big baby - OK, so, they didn't say that last bit :-). It really is bl**dy annoying.

I recently replaced the front shocks (140k miles), and even then they said the compressor was ok / not the cause of the fault light. This fault has been there right from the beginning of my ownership, albeit it flashes up almost constantly these days versus only occasionally when I first got it.

My solution is to affix an piece of cardboard to cover the offending light when it puts in an appearance! Is this really the only way to fix it?

Any help gratefully received. Thank you.
Mike

 

Do I read you correctly?

You have done 180k miles in your Jag and never replaced the compressor seal??

If this is correct the compressor must need a new seal by now!

I suggest you buy a new seal kit from bagpipingAndy on this forum (35 GBP)

and fit it then see if it solves the problem.

BTW it is not a 'known fault'

 

Hmm.. If not "known" at least "common" and "frequent". The air compressor is the one component on the system that is known by dealers and owners to have a short life.However, we now know it is just the piston seal that fails and 'bagpipingandy' sells a replacement kit. Obviously at some point the motor will start to fail but much later in miles. Service exchange compressos are available widely, plus not-too-expensive new ones on the internet.

 

I have similar issues to the original poster. And I'm concerned that I will spend many hundreds of dollars getting to "no diagnosis." This is on my 2004 XJR, 56k miles, no suspension work yet:

- air suspension warning light maybe 25-35% of the time I drive the car
- C2303 and c1830
- car is never too low, never receive message about car being too low
- doesn't seem to be related to ambient air temp - happens when it's 30 deg or 70 deg
- took it to an independent mechanic who said (1) compressor integrity ok; (2) no power to air compressor wasn't receiving power. Tested the relay and it was ok. Found loose connections in relay leg, reseated it, deflated front suspension and it reinflated fine. But a few days later, the faults returned
- Some times the fault light comes on almost immediately after starting the car, so it's not waiting 200-300 seconds. Other times, it does take a little longer.

The car drives as it always has, so I've come to accept it for now.

 

I'm having exactly the same experience as hanfrac above as my "air suspension fault" will light up hot or gold, fair or rainy, immediately or sometimes longer. The car never settles too low either all around or at one corner. their seems to be no rhyme or reason to it so at the moment (59k+ miles 2004 XJ8) I'm leaning towards an electrical glitch from a complex system. I'm also having some weird issues with the "auto on/off" function of the headlights as they turn on immediately regardless of time of day or night and when I disable the auto function it warns me that my "light switch is off", well duh, I just turned it off dummy !! My AM/FM mode on the audio system often switches from the FM band to the AM band all on its' own but I attribute that to electrical interference from the increasing presence of spurious signals of every type from cellphones to traffic cams, etc.

I often think that many of these unexplained 'glitches' happen because the system is not well armored against the very signals that our society has grown to depend upon increasingly over the past 2 decades. Years ago (mid-80's - early 90's) we had serious problems with just this kind of problems when the newer more electronic models got near installations like Cape Kennedy where the airwaves were flooded with powerful radio and radar waves as a matter daily life.

 

Happiness is none of the annoyance with my coilovers.

 

First thing to do is clean your 3 front earth points (grounds).
Many gremlins caused by this. Do a search on this forum for more.

Next, replace your air compressor fuse, even if it looks ok.

After that it may be a little more involved.
Start with the easy stuff.

 

What happens with a failing compressor is you get the fault message, because the ASM has detected that the reservoir is taking too long to charge up. This is caused by a failing compressor, but it is not a sudden failure, more a slow death, and caused by the piston seal failing, (although clearly the motor can wear out too !). C2303 is the fault code indicating this fault, and I had this in late 2010, and a service exchange compressor cured it, (as of today 30th March 2013). If I keep the car a long time, no doubt I will need another replacement just like a pair of tyres. OK ,its a nuisance but at least I know what it is so don't have any more worries.

 

I'll be the first to admit the air suspension system on the X350 can be a nuisance at times but if I was looking for a another X350 I wouldn't buy one with coil-overs at any price.

 

Frasier - here's the problem:

- sure, we all know that the air compressor fails and needs to be replaced
- lots of people have replaced or refreshed their compressor and their errors are gone
- however, given that some of us are getting the error firing immediately upon start-up, it is unlikely that the the ASM has enough time to figure out whether the compressor is doing its job. If I start the car up and within 10 seconds, the fault fires, it's not this, right?
- which is the core problem - what problem are we chasing? I tend to believe that this is an electrical problem, as tomfurie and RDMinor are hypothesizing

And what I'd love to do is avoid going to a mechanic, spending a bunch of money to solve the wrong problem at great time and expense. If my compressor is for some reason still good (as my mechanic believes), then I'm solving the wrong problem by buying the new seal.

I'll look into the "front earth points."

 

Could you post the fault code being thronw up by the display. It is this that should give a clue on the problem.

Other thing to note is that I have been told that with cerrtain faults, the fault can appear on start-up because the fault codes haven't been cleared from the original fault flag time even though the reason for the original fault has disappeared. However, after a certain number of start-ups, it is suppressed, but the fault code remains in memory. I had this with the CEL last year.

 

Let me ask you something, does this light comes on when the headlight stalk is activated?Is the autolamp activated or deactivated?Does the suspension falut come on at night while driving or off? and have you had the codes read?It may not be a plausability code at all.

 

I started getting air suspension fault warnings in Jan/Feb. No problems with sagging shocks, no apparent leaks, no "car too low" warnings. C2303 and some other warning relating to the electrical charge.

4 visits to my local mechanic:
1 - diagnose system, look for leaks, deplete a shock and verify that it refills, etc. Thought they had a problem getting power to compressor, reset relay. $160. Problem returned within 2 days
2 - revisit codes, more system observation. At recommendation of members here, cleaned grounds. $60
3 - more evaluation, checked codes, checked battery, found battery had low charge, replaced battery - $240 (probably was due for a battery, as it looked like it was the original battery that shipped with the car)
4 - ordered bagpipingandy's kit, had it installed. $60 + $220 labor

One week later, I have had no suspension fault warnings. So I apologize to Frasier Mitchell for being resistant to this as a possible solution. And thanks to bagpipingandy for solving this eternal mystery.

 

I am wondering if you still have or have had no air suspension faults to date? Thanks!

 

Hi guys, well I have the same issue. It started when it got cold here December, and then I had a brand new compressor fitted, and the problem was gone. Before that, the fault would stay on even after restarting the car. Now it goes away when the car is restarted, and may not come back for several days. I have noticed that as soon as the fault comes on, the car becomes stiff. Also I have noticed that recently when I drive around, I can see the car just lifts it self after a full stop at a traffic light. Normally the car is ALWAYS in my garage and it doesnt get colder than 7 degrees C, but after it stayed outside just once, next morning this fault came on for the first time after the compressor has been changed, so I can conclude that the cat doesn't want to stay outside

 

Hi XJRLondon2004,

I'm sorry to hear you're still having suspension troubles. My first suspicion is that you are experiencing the common air leak at one of your air springs that worsens in cold temperatures. You can check for leaks by using a spray bottle to spritz various connections with a solution of water and washing-up liquid (liquid dish soap here in the U.S.). Test the air hose fittings and top rubber seals at the tops of each air spring/damper, but take care not to wet the CATS electrical connectors. Also test the air hose connections at the valve block and air reservoir tank, which are in the boot under the spare wheel. A leak at an air hose fitting is usually easy to repair.

I have a leak in the top seal of our front right air spring, and as far as I know, no one has yet figured out a do-it-yourself repair of the seal, though I intend to try at some point. For now I'm just living with the occasional need to restart the car two or three times on cold days to let the compressor run for its allotted 2 minutes, turn off the engine for 45 seconds, restart and let the compressor run again, and repeat until the car is high enough that the VEHICLE TOO LOW warning goes away. If you just pull away and drive the car before it has reached its correct ride height, you will typically trigger the AIR SUSPENSION FAULT (ASF), which in my experience prevents the compressor from running again until you shut off the engine and give the system time to reset.

Have you scanned the car's modules for stored Diagnostic Trouble Codes (DTCs)? If so, report them here and our knowledgeable members may be able to help.

Cheers,

Don

 

Coincidentally, I just spent yesterday installing bagpipingandy's rebuild kit.

Thanks to his instructions and videos, DonB's description and photos, and Jaghelp.com instructions posted recently, it is a reasonably straightforward job. It's a little futzy getting the collars and springs in the proper placement while holding the compressor up, but other than that, it is relatively easy.

As these cars age, I would recommend installing the kit as simple preventative maintenance even if you aren't getting any Air Suspension Fault codes or warnings.

 

Hi, thanks for your reply. I did change the whole compressor, I got a brand new one at the dealer. I have never got the message that the suspension is too low. I have noticed that when I drive over a bump, the RIGHT side suspension clunks, after I changed the air compressor, the clunk almost went away, but now I feel that it is back again. As if there is not enough pressure on the system. Maybe there is a leak on that shock?

 

Hi Don, thanks for the message. I never got a "too low" message. I get the fault after like 20-30 mins after I start driving. Then everything becomes stiff. Weird thing, is that if you don't get the code scanned when the error appears, then after a restart there are NO fault codes in the ecu. I have this WIFI OBD thing I use. I will take it to the dealer today and see what they can find, I will tell them to look for leaks as you described, I hope they find it. But if it is one of the shocks, then I know how much it is going to be

 

good work , sorry ive not been on here for a while, but good to hear you are solving the suspension issues, keep up the good work

Andy