Hello,

I saw many posts about this issue but I wanted to see what you all think with my car since we all have unique conditions.

I've been getting an intermittent "Air Suspension Fault" yellow alert that would go away after the car is started again. I live in Miami, Florida. Usually it is very warm, but last night it got down to 51 F (that's 10.5 C). I didn't drive the car today, it was driven yesterday at not more than 35 mp/h (56km/h).

Tonight I noticed it was very low. All 4 corners seem to be at the same height.

I started it to go out for a drive but it had a red alert that said "vehicle too low". I could hear the air compressor coming on and off but the car wouldn't rise. I didn't drive it.

Then I tried again an hour later and from the moment I opened the driver's door I could hear/see it started rising and once I turned it on it kept rising and the red warning light "vehicle too low" was gone.

From what I've read from all the posts, I'm hoping it is bad air reservoir?

I'm going to call a local Jaguar shop to see what they say, I'll most likely take it in as soon as they have an opening. In case the "vehicle low warning" appears again is it possible to drive it (shop is about 4 miles away) or should I tow it in on a flatbed truck?

It currently has 26,800 miles and this month it is 10 years old. Me and my family are the original owners.

Thanks for any insights.


Front, Driver Side.



Rear, Driver Side.



Front, Passenger Side.



Rear, passenger side. This one seems to be at normal height.

 

Hi Frank,

A suspension sitting low is typically the result of an air leak, and some leaks seem to show up in cool weather and disappear in warm weather.

You mentioned initially that all 4 corners seem to be at the same height, but then you stated that the rear passenger side corner seems to be at normal height. Before this occurred, had you ever visually compared or measured the ride height of each corner? If not, is it possible that the rear driver's side corner has been a little lower than the right side, but you haven't noticed?

Here's my initial theory: You have a leak in the top seal of one of your front air springs. Leaks at the top seal seem to leak faster in cool and cold weather. Both front air springs are tied together in the valve block, so a leak in one air spring causes both of them to collapse. When the front end drops all the way to its bump stops, it drags the rear corners down as well. If one rear corner has been riding a little lower than the other, it will now appear even lower in comparison.

To find the leak, you can spritz a little soapy water around the air hose fittings and around the top center section of the air spring (just take care not to wet the ECATS electrical connector). Bubbles indicate a leak. If you find a leak at an air hose fitting, it can probably be repaired. If the leak is at the top seal of the air spring, there is no easy fix and the only permanent solution is to replace the air spring/damper.

I have been living with this for two years, and the way I get around it is when I notice that the car is low, I start the engine, leave the gear selector lever in Park, and listen for the air compressor to run for as long as it will (up to 120 seconds before it times out to allow the cylinder head and piston ring to cool). If the VEHICLE TOO LOW (VTL) warning disappears, the car has risen sufficiently and can be driven. If the warning remains, turn the engine off and wait 45 seconds. Now start the engine again, leave the gear in Park and wait for the compressor to run again until it times out. This will usually raise the car enough to extinguish the VTL warning and avoid the AIR SUSPENSION FAULT warning. Worst case, you may have to repeat a third time. Once you put the car in gear, the compressor is shut off until the car exceeds 25 mph, which may not happen soon enough to avoid the ASF, so that's why you have to leave the car in Park and wait.

I haven't heard of any examples of a bad air reservoir, so I'm wondering if what you've read about is the C2303 Reservoir Plausibility Error fault code that is often triggered when the compressor cannot pressurize the system in the time allotted by the Air Suspension Control Module (ASM) before triggering a fault. What has eliminated or reduced this problem for many of us is to replace the Teflon piston ring/seal in the compressor using a kit from our forum member bagpipingandy (bagpipingandy.com or info@bagpipingandy.com).

Your car has done very few miles for its age, so it's possible your piston ring is still fine, but it's easy and inexpensive to replace.

Please keep us informed.

Cheers,

Don

 

I would add one last advice to the very good recommendations of Don.
In my case, as even several attempts of the compressor did not succeed to raise the car when parked in cold (much colder here in Belgium than in Florida), letting the engine warm up the engine bay, then stopping/restarting it allowed a successful restart of the compressor and raising of the car.
Apparently the (bad) sealing on top of the defaulting airshock in cold was sufficiently recovered when warm.
Hope it can help, at least to be able to drive to the shop and change the bad shock.

 

When I bought my 2003 XJ6 in 2010, it was on 30k miles yet only a few thousand miles later I had to have a new compressor. This new compressor was still on the car when I part-exed it last October for another XJ6, a 2007 one this time.

A 10 year old car on 28k miles as your's is suggests it stands a lot of the time. Jaguar's own technical notes of 2003.5 of which I have a copy admit that the system will have small leaks. The car, if left standing, will wake up every 24 hours to check the vehicle height and let air out of springs to keep the car level, (it doesn't start the compressor, or try to increase the height). So as time goes on the car gets lower and lower. Use every few days ensures the reservoir gets topped up.

Don B is right that the air springs can suffer leaks at the top seal, especially in colder weather. A very slight leak can be lived with if the car is in regular use but over time standing, the car will end up on the bump stops.

 

I recently carried out a systematic and detailed observation of the heigth of my car as I noticed more and more landings during the recent cold period.
My car is also 10 years old and has now 60k kms but has probably suffered from hot temps that may have taken a toll on the shocks in its early life (was sold to a Qatari emir).

I noticed that indeed the car is levelled everyday to compensate for leaks, but not only, because it also recovered some height every morning compared to the evening before, in particular on the front (the rear lowers less than the front in my case).
This up to one week, as stated in the manual, or until the reservoir is emptied if too strong a leak (that can happen in only one night if it's too cold).

 

Thanks for all the insights. The car had been driven the previous two days (Saturday Sunday) the problem appeared and on Thursday it was driven about 50 miles on the highway.

Before this problem occurred it always seem to be at the same height on all 4 corners. I just called the shop to tell them I would change the front shocks for the Arnott, he told me I could just do the bad one but I told him that both sides were low so it was difficult to be sure which side it was.

I think Don B, that your initial theory is correct and it is what the shop seems to think. I went there this morning in my other car since I wasn't sure if they'd be able to take the Jaguar today. The shop owner told me that the Arnotts make a little noise which I can live with instead of spending $1,300 for 1 original factory part. Anyways if I ever part with the car, nobody recognizes all the repairs and such when appraising it's value.

 

Frank,

Before you commit to Arnott, it would be prudent to confirm with them that their units have the resistor to fool the ECATS system so you won't get the CATS FAULT warning lamp on the instrument cluster. As I understand it their units do not support ECATS adaptive damping functionality, but they do have a means of fooling the Air Suspension Control Module (ASM) so it doesn't trigger the CATS FAULT. You might also ask them about the effect on vehicle dynamics if the ASM switches the rear shocks between soft and firm but the front Arnotts do not change.

Not to try to talk you out of the Arnotts, but OE Bilstein units are available for far less than $1,300. I've recently seen them listed on eBay for $680 - $750 and there may be even less expensive options elsewhere.

Cheers,

Don

 

My '08 XJL seems to be affected by the cold weather. It has 66K miles and spent most of it's life in the Carolinas until this year. It's the first cold winter it has experienced.

The car was parked outside all night and the weather was in the single digits Fahrenheit. Both front shocks were down to the bump stops. I tried turning it on for a few minutes, then turn it off, then turn it on again. Thought was it would give the compressor time to pressurize everything, but it didn't work. My son drove me to the office and parked the Jag in the garage. After an hour or so he started it and the front end rose up to normal height with no faults. The next day, the temp was in the teens and the front end was down again. It rose up when I started it but after a short drive, the Air Fault light came on. It never said the car was too low. Today the temp hit 60! and no problems.

I was reading Don B's sticky about the suspension (thanks Don) and it was very informative. Will have my shop check for air line leaks first. Lets see if it's not the shocks.

 

Hey Don,

So I saw your post after getting back from the shop today. I didn't know the XJ8 had ECATS and that the Arnott struts didn't support it. I would have considered the original shocks if I knew this. I just looked tonight and didn't find new ones on eBay but Rockautpoparts.com had them for $998.00 each.

Originally I was going to convert to the coil system, but then I thought that if I change all 4 struts the difference between the Arnott Air and the Arnott Coil with labor (about $250 each) was $1,000. So today I just changed the front ones for the Arnott Air. When I got the car back it felt taller at the front or more stable, it was a different feeling difficult to put into words, but it felt good. I just took it out on the highway and it rode very nicely.

If money were no object I would have gone with the Bilstein/Jaguar originals but these Arnott Air seem to be a good compromise, so I think that still knowing about loosing the ECATS functionality I'd still go with the Arnott Air.

I have a Corvette that has magnetic shocks, there is no generic version for those. They retail at the dealer for about $1,000 each, when they reach the end of their life I'll just switch to regular shocks; there is a solution for tricking the car into thinking it has the magnetic shocks. If I win the lottery before then, then I'd get the magnetic ones and change the Arnotts for Jaguar originals. :-)

When this XJ8 was about 2 years old my mom drove into a concrete island and one of the front rims broke, so I think maybe that weakened the shock back then so that's why it only lasted 26,000 miles. I know age is a factor too though. I'm going to go back to get new front brakes/rotors in a couple of weeks so I'll ask my mechanic what he thinks about the rear shocks still being under ECATS and the fronts not being so. I'll attach some pictures of the new struts for everyones benefit.

Thanks Don for all your help.

Frank

 

Hi FrankZ06, your thread has been very timely and helpful.

My wife's 2004 XJ8 had a new drivers side front air strut installed just before we bought the car almost 2 years ago. We were told it was done at the Jaguar dealer so we assumed it was a Jaguar part. It seems to be time to replace the passenger front air strut now. While doing my research I found that the new one on the drivers side has the exact same markings as your picture above (Arnott Air suspension products 29-4494), so it's not OEM Jaguar. So, she has driven it for the last 20,000 miles with an OEM Jaguar on one side of the front and an Arnott on the other side. Drives wonderful and no suspension codes.

I guess that means I'm safe ordering another Arnott for the passenger side without any concern of degraded driving quality or annoying error messages.

I'm guessing the one you have pictured that has the 29-4494 number on it is actually the Arnott part number AS2710 that I see listed online everywhere?

 

Hi Jeff,

I'm glad to hear the thread has been helpful. Yesterday I called Arnott to verify as Don said that the ECATS functionality is lost, they said it is so but that the system really comes on when you are going over 100 mph. I think there might be more to the ECATS than that. They should put this warning on their website so people are informed before buying and installing it.

You should be okay driving with another Arnott on the passenger side. I replaced both fronts at the same time, the car felt more stable or sporty. Last night I went over a speed bump (slowly of course) and did notice that now at the front there is no bounce, at the back with the original 10 year old, 26,000 mile shocks there is one slight extra bounce. The car rides very nicely. This morning when I started it, it pumped some air into the front struts and the car lifted a little as it would normally do before.

I didn't get any error messages at any time. I had them installed by a local shop that specializes in Jaguars. When I was talking to the Arnott rep last night he told me that if a warning ever comes on that it is very easy to fix, that it is just some resistor at the top of the shock that has to be changed. I didn't understand completely so whoever has this problem with an Arnott better call them to ask.

The shop ordered it for me so I am not sure which part number matches with the one online. I would call them and ask them to be sure you get the right part. They have two variations, one for the Sport Suspension and another for the Comfort Suspension. On the other side of the shock it has a sticker that says "Air Suspension by Contitech". At first that was confusing, I thought I got some non Arnott part, but on the label it has the small Arnott logo. I called them and they told me that they use the rubber parts from Contitech since they make some of the "best rubber parts".

If you order it from Arnott directly you can get lifetime warranty on the part. My local shop gives a 1 year warranty, which also includes the labor. I figure even if I get a lifetime warranty on something and still have to pay the labor to take it off and back on it is too much of a hassle.

The website for Arnott is arnottindustries.com

Let us know how it turns out.
Frank

 

Frank,

You are correct that there is more to ECATS and the Arnott representative was wrong. I recently compiled a summary of the air suspension and ECATS components and operation that explains how the adaptive damping works:

Air Suspension & ECATS System Summary: Components & Operation

The owners whose cars I've converted to the Arnott coil-springs don't seem to miss ECATS, so hopefully you'll be very happy with your Arnott air springs.

Cheers,

Don

 

My car is a 2008 XJ8L with just over 40K miles.

For a few months in 2006 it was doing the "Air Suspension Too Low" message. Right front shock went down most and right rear somewhat with left looking okay. This happens every time the car sits for 2-3 hours. The tank in the truck would fill until it ran of air.

One day I accidently bumped the drive mode to off(always on sports mode before), then this air shock problem went away. I has not come back even when car sat for a week during Thanksgiving with 35-60 degree weather. The height of all four wheel well are about 27". So I drive it in normal mode now.

My question is what I can do preventively before it happens again. I don't think my shocks are leaking but maybe some sensor is out of calibration.

Thanks,

 

I meant in 2016.

 

I have coils and one thing I didn't care for with CATS was the nervously stiff feeling I would get at sustained higher speeds. I was concerned coils wouldn't feel as planted but that's not the case. It does ride a hint stiffer but it feels more predictable overall.

 

Hi yutrade67,

I can't think of any possible connection between the Drive/Sport transmission switch and the air suspension, so I believe your circumstances must have been coincidental.

If a sensor was out of calibration, the car would not raise to a reasonably level and correct ride height. The most likely culprit is an air leak.

In an air suspension that is working properly, the only route for air to exit is via the exhaust vent solenoid valve in the air compressor. The Air Suspension Control Module (ASM) awakens periodically to check the level of the car. If it is parked on an inclined surface, the ASM will vent air from the higher end to bring the car as close to level as possible. This is programmed into the system because research showed that people prefer to enter and exit a car that is level.

If the car is parked on a level surface, little if any air should be exhausted and the height of the car should not drop much if at all, unless the ambient air temperature falls, reducing the pressure in the air suspension system.

When one right corner drops, it is usually due to an air leak at that corner. The leak could be in the air hose, air hose fitting, pressure retention valve, air spring top seal, or air spring bladder. An intermittent leak like yours is probably in the top seal, an air hose fitting, or the pressure retention valve in your front right air spring. When a front corner drops, it pulls the rear corner on the same side downward, so your rear air spring is probably OK.

You can check for leaks by spritzing soapy water on the air hose fitting and pressure retention valve and around the top seal, but take care not to wet the ECATS electrical connector. Bubbles indicate a leak.

There is a lot of info on the air suspension on this forum, and you might want to start with the summary at this link:

Air Suspension & ECATS System Summary: Components & Operation

Cheers,

Don

 

Voltage plays a huge issue in all things staying in balance. I wouldn't have thought too much of my issues until the alternator was swapped. Might be worth checking the battery especially if it's fine after a restart and since the car sits a lot. A battery tender would be a good idea. I had flickering headlamps and slightly longer starts but it wasn't until the alternator started making noise that I replaced it. I didn't think I was having any real charging issues until after it was replaced.