There is a dedicated thread on this topic by Brutal. Do a search and wade thru the topics and you will find it. It involves building an air pressure test device with hardware store parts. Works like a charm.

 

XJR- this side to side motion is not normal. You should get it looked at. I suspect bushings, possibly tires.

 

Glad to hear it's not normal. Any recommendations for where to go to check it, in the Los Angeles area? I'm on the west side, but have never loved the closest dealer here. (tires are new, no other sign of looseness in terms of bushings...)

 

Here's the thing. The compressor does not operate with the ign. sw. off. Therefore, if the ride height, front or rear, drops down over night, say 2 to 4", you probably have a shock leak. Air lines, tank, etc. rarely leak. Right front shocks go bad 1st as they take the worst beating.

Say the rt. ft. is leaking. Periodically during down time the system checks itself and will lower the lt. ft. to even out the ft. side to side ride height.

Say you get an air suspension error code on your dash display. That is inconclusive as the problem could be either air shock leak rate that a good compressor cannot keep up with or a worn out compressor that can't keep up with "normal" air demand.

Do a search. Look for a series of posts from stevtech or steve11, same guy. His analysis is much more detailed and factual than mine could ever hope to be. Which reminds me. We haven't heard from him in a long time. I think we tend to burn out out service tech members as they have to keep going over the same old stuff over and over. No criticism implied as it is just the nature of a dynamic forum such as ours.

 

My guess is that a $200 calibration will be a waste of time and money and will produce nothing.

If you have no other symptoms, such as a badly sagging front end over a week end, my vote is for a weak air compressor. A one or two inch jump-up of the front end after a cold start is no big deal. But, the air suspension fault code is a clear warning that something is going South.

How often do you get a thrown code?

 

It also sounds like a weak compressor to me. It should be easy to replace yourself. I hear on US models it's right behind the front bumper in front of the front wheel well on the driver side.

 

today it was cold here, and after driving my 04 xjrs for a i/2 an hour, i get the air suspension message on, and the temperature jumped all the way to the red, so I had to pull to the side and shut it off for few minutes, i started it back up and the temperature was fine but the amber light stayed on and the air suspension message stayed on, drove the car to the mall ,went shopping came back and checked the antifreeze, it was full, drove back home, another 1/2 hour drive the temperature acted the same, i had to shut the car for few minutes and then restarted it , i drove home parked the car for couple hours .then took the car for a small ride the air suspension message and light disappeared . some help ??? please .

 

I have a 2004 jaquar xjr my air suspension is down I know a little I check the fuses ok I put a test light on the red wire on the air motor I get no fire no 12 volts I don't live where cold weather can some one e mail or post the ans. on this forum my e mail ttomsauto@aol.com thanks for any adv.

 

Hi ttomsauto
You need to be a little bit more forthcoming on what is going wrong with your car, you have given us too little information at the moment. For your information, the air compressor does not have 12v to it all the time, it is switched on when the ASC decides more air is needed in the reservoir in the trunk.

 

My 2004 jaguar is not in cold weather I live south Texas I front end is down howdoi check it is it my compressor r the air strutshw will know I check fuses all good I don't have a scanner to check how can I pull codes we don't have a dealer ship here thanks for any help

 

Front end down too far can be caused by one of two things: -

1. Front height sensor is duff
2. One or both of the front springs is leaking.

There should be fault codes associated with the message you get on the annunciator display. These need to be read to determine what might be wrong. Some dealers (look up forum member "Brutal" who is in Texas), have built themselves a clever little rig to check for leakage of spring units. Car sometimes has to be left overnight if its a slow leak. Most shops dealing with Jaguars can read off the codes and get the description. Note that notall retail readers translate all the codes, you have to get the Jaguar table of codes and descriptions, probably on this forum somewhere.

BTW a hiss of air shortly after engine shutdown is normal action of the system blowing out the water trap in the compressor.

 

What the best way to check my front air struts and compressor the front end is down I don't here the compressor turning on I check all the fuses ok should I raise the front end with a small jack to see if the compressor turn on or should I run a wire from the bat to the red wire on the compressor harness to see if it come on is there a way to put air on the the struts using a outside compressor to see or hear if the struts are leaking

 

Hi, just a quick question. Should my air suspension adjust itself when I come to a stop and apply the handbrake. Mine is always doing it. Thanks

 

Can you expand a bit on what is happening, please. I don't think you have any problem though, if you have no fault messages.

 

Yes that is absolutely normal. It will also adjust without applying the hand brake at times.

 

Thanks for that. I now need to sort out the horrendous ride im getting. Sometimes it feels like Im driving over a cattle grid. What was wrong with the old spring and shocker.

 

Please see ? Double the life of your air compressor and Air Suspension Fault FIXED - for now...
These compressors are assembled in many cars so you should be able to find an indie for the installation of the piston ring.
Please don't forget to check your battery, the air line connectors and earth (ground) points of the headlamp units.
If the front shocks or multiple components turn out to be replaced, consider to switch to spring struts from Arnott, Motorkars or Strutmasters:
Suspension Options Super Thread! - Jaguar Forums - Jaguar Enthusiasts Forum

Good luck

 

If I understand nellerbeck's post, it was not the air line or hose that was leaking, but the fitting for the CATS sensor where the electrical connector attaches to the top of the shock.

Nellerbeck, could you please clarify?

Thanks!

Don

 

For those who determine that their air compressors are not pressurizing the system properly, rebuilding the compressor is pretty easy using the Andy Fulton's inexpensive replacement piston ring that he manufactures himself (bagpipingandy.com). Below are links of photos showing how I replaced the piston ring in our compressor, cleaned the check valve in the cylinder head, and replaced the molecular sieve desiccant beads in the air dryer. Replacing the piston ring alone would have cost me just U.S. $48.00 including shipping from the U.K. Replacing the desiccant cost another $50.00 or so. Still FAR less expensive than replacing the entire compressor, which in our case, with 80K miles on it, appeared to be ready to easily go another 80K miles with no discernible play in the piston connecting rod/crankshaft joint and no noise in the motor that would indicate anything amiss.

Cheers,

Don

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