I have read through many of the Air Suspension threads, but have not seen this question addressed. Thank you in advance for continuing on...

In December, I had the passenger side front of the vehicle drop after a long cold snap. At that time, I had the front air shocks replaced.
Since that time, I have had periodic Air Suspension Fault messages. The car has not dropped other than on the one occasion.

When code reading, I recieve the Reservoir Plausibility error.

While checking for leaks I disconnected the air lines from top of the strut, releasing all air pressure. The car sunk as expected. Please see pic.


On the base of the drivers side air connector, a greenish gunk which may be the result, I suspect, of some copper reaction with water vapor that is pumped into the shock. Please see pic. So I wiped the green away and re-attached air connector.

On the passenger side, no greenish residue. Please see pic. I re-attached the air connector.


So, here is the interesting part (maybe).
After connecting both connectors, I find a small copper colored ring in the honeycomb area near the shock tower. Please see pics.

So now, I am wondering if this small ring connects to the end of the air shock connector. It seems possible as the copper 'ring' has a groove inside which appears that it might go around the rubber ring at the base of the air connector. I have not diconnected the air fittings again to test fit the copper ring.

Is it possible that while the shock replacement was done, a ring came off the base of the driver's side connector, resulting in periodic fault messages? And now I have 'found' a second ring (from the second air fitting) that has also come undone?


Please advise if you have disconnected these air fittings or send a picture of your connector for comparison.

If the brass 'ring' is not a part of the connector, I will continue diagnosing the issue with the soapy water and then, follow with the compressor rebuild kit.

Thanks in advance
-mag

 

OK, I am seeing a similar Land Rover part on eBay...

New Genuine Land Rover Air Suspension Compressor Spring Fitting for Disco 2 | eBay

By chance would the Rover part fit the Jag?

 

That brass fitting is part of the compression fitting on the top part of the brass connector you are holding in the picture. It goes on the plastic air line that screws into the top if the shock. The new Arnotts you put on would have come with new brass connectors (the big piece in the pictures) AND new compression washers (your unidentified part). You likely found the old one left over from the shock change.

 

Still trying to understand this...

I dont believe there were replacement connectors with the Arnott kit, unless they were missed...I may need to give them a call and verify.

Does the large fitting come apart and the small piece fit inside? or is the small piece installed in the threaded end? or installed at the air line end?

In which area is the 'ring' (ferrule?) to be installed 1, 2, or 3? How can I know that this part is not needed?

Thanks again-
mag

 

Separate #3 from #2...it goes in between the two on the plastic air line. Take a peek.

 

The "Reservoir Plausibility Error" normally indicates the air compressor is failing to charge the compressor within the allowed time, thus indicating a compressor fault. This fault is very common, and is due to the piston seal wearing out. So your fault may be totally unrelated to your new front spring units.

The component with the shortest life in the air suspension system is the compressor. Having said that, it is normally the piston seal and a new one is now available for the DIY guys from a chap called "bagpipingandy". BPA made these for an Audi compressor but they are the same as the Jaguar. BPA is a forum member, so send him a PM to see if he has one in stock. Failing that, you can buy compressors on the internet for around £300. Fitting is a 30mins to one hour job.

 

I don't know about a possible cross fit but go back to your eBay link and look closely at the three pictures of the actual fitting. Pay close attention to the changes seen in each photo at the THREADED end. To me it looks as if the brass split collar that you found in fitted into the threaded end with the beveled end inserted into the threads.

Of the three pictures of the actual part look at the middle one first and then the one to the left and see if I may be correct.

I agree with the previous post in that the parts you found are probably the old compression collars from the original fittings which may have been replaced even if the fittings weren't in order to properly set with the new air shocks.

 

And, I can't remember if you are already in it.

But at the top of the forum we have a Prize Draw for 2 of BPA's compressor repair kits.

AND THIS CLOSES TONIGHT!!

 

Yes, that is what I thought I saw in the second pic. Hoping to confirm location of this small collar with a jag photo if possible to verify its proper location. The rings are small, so I am thinking that they could easily be overlooked or dropped.

No dash message yesterday, so I will continue the investigation...

Thanks-
mag

 

Fingers crossed, I am in the drawing...

Failing that, I will PM BPA.

Thanks
-mag

 

My air suspension fault msg. came on for my 04 XJ8 with 78,000 miles on it, but only when there were people in my back seat(approximately two). When riding with only front passengers nothing happens, but noticed a small sag on drivers rear side and also hears a hiss for about 10 secs when I get out. Can anyone help me solve this issue?

 

The 10 sec hiss is normal, and is the system blowing air back through the air compressor to clear water out of the water trap. So nothing to worry about there !

You need to read, (or get read), the fault codes. I suspect your air compressor is on the way out. If you have fault code C2303 then it is almost certain to be the compressor. A piston seal kit will probably cure the problem if you are a DIYer, or know a shop that can replace the piston seal. If not, a service exchange compressor will sort it out.

 

Ok, I'll get a diagnostic ran on it...but what could be causing the slight sag on left rear side?

 

Wheel height is controlled separately at the rear, one height sensor per wheel, so it might need recalibrating. There is a special height setting tool and PC program to do this. Fronts are controlled as an axle (only one height sensor).

 

As mentioned a couple posts earlier, if you have the reservoir plausibility code it is probably time for a compressor rebuild or replace. I replaced a couple of front shocks trying to sort this out and still had the reoccurring reservoir plausibility error.

Following the repeated occurrence of the reservoir plausibility code (even after the shock replacement), I used BPA's compressor rebuild kit and have not had a suspension message since.

If in this situation again, I would probably do compressor rebuild first and follow up with shocks if the problem remained.

Thanks-
mag

 

The moral of this tale is to not rush in and replace very expensive components before an investigation has been done, and the fault codes read and considered. When I got "air suspension fault" in 2010, the Jaguar dealer read the codes and told me the air compressor was on the way out, (and this was a 32k miles car, BTW!!), so I agreed a replacement and Bingo ! No faults since !

 

I have just replaced a right front air shock that was definitely bad. I also rebuilt the compressor with one of Andy's kits and the front shocks came up to the correct height after about a mile and the 'vehicle level too low' message went out.

Unfortunately the 'air suspension fault' message appeared and is being repeated IMMEDIATELY upon engine restart without waiting any length of time at all. The front end hasn't lost any height since the install and the compressor doesn't seem to be cycling even when I'm stopped just idling.

Has anyone else had this similar problem after either a shock install or an extended period with the battery disconnected? I had mine disconnected over night while I was working on several maintenance issues including the compressor rebuild and I've noticed a couple (so far) of anomalies that would indicate a programming memory loss.

 

Hi, does the air suspension system operate ok, does the actually compressor run when it needs to?

is the error on constantly?

check the earth behind the headlight is ok, not sure its exact position but other jag owners will advise soon im sure, also check the compressor wiring connections and any others you may have unplugged to check they are all ok and still plugged in, I'm basing it on an electrical error could cause the error to be on constantly,

regards

Andy

 

With the new piston seal the compressor will probably run quieter and I can only just hear mine running.

Try reading and clearing the codes. Compressor relay is a possible also but sounds like a "funny" to me.

Hey you fixed the shocks which is the main thing!