We were getting an Air Suspension Fault message earlier when driving in cold conditions. Now it occurred when only 68 degrees. My wife says she can feel every bump when the air suspension is not engaged.
How can I troubleshoot this? The nearest dealer is a 4-hour drive away.
Thanks,

Mark

 

Hi Mark,

I have moved your post from the forum for the X308 to the forum for the X350, which is the Jaguar factory project code for your 2006 XJ8. Here you will find knowledgeable owners of similar cars.

The most common cause of the ASF in cold conditions is an air leak from the top seal of one of the front air spring/shock absorber assemblies. The top seal is a large rubber molding and one edge of it can be seen around the circular recess in the top of the air spring (viewed from the engine bay). With the air suspension fully charged, you may be able to see air bubbles at this seal if you spritz a little soapy water around the top of the air spring, taking care not to wet the electrical connector for the ECATS solenoid.

Another typical contributor to these symptoms is a worn piston ring/seal in the air compressor. The seal is made of PTFE, a type of Teflon, and when it becomes worn the compressor cannot pressurize the system within the time allotted by the Air Suspension Control Module (ASM). This triggers the ASF warning on the instrument cluster, You can replace the seal yourself using an inexpensive kit from our member Andy at bagpipingandy.com.

It is also helpful to have your car scanned by a diagnostic system capable of reading the proprietary Jaguar Chassis (C-prefix), Body (B-prefix) and Network (U-prefix) Diagnostic Trouble Codes (DTCs) which are triggered by air suspension problems. Knowing the DTCs can help narrow down the diagnosis, but standard generic OBDII scanners can only read the Powertrain (P-prefix) codes. Find a local shop that works on European cars with the dealer-level Jaguar IDS/WDS/SDD diagnostic system, or a high end scan tool such as an Autel MaxiSys, Launch X-431, or AutoEnginuity with the Jaguar enhancement. Some Snap On scanners may also work, but their coverage of European cars tends to not be as thorough as the tools from Autel and Launch.

You might also have a look at the thread below, which will help you understand the air suspension system:

Air Suspension & ECATS System Summary: Components & Operation

Please keep us informed..

Cheers,

Don

 

Spent Christmas Day replacing the piston ring provided by Bagpipingandy.com in preparation of a 1100+ mile road trip the next day. When finished we drove around town for a while looking at Christmas lights with no Air Suspension Fault light coming on. Next day we took off feeling confident that the problem was fixed but did not even get out of town before the light came on. It is not an issue on the interstate (except in New Mexico), so we proceeded to California. Since then it has been intermittent but has come on even in warmer weather. Now I will try to seal the tops of the air spring assemblies.
On that note, I saw a few bubbles coming out of an opening in the top of the ring. Those openings are obviously there for a purpose. Should they be sealed up? Some pictures of exactly where I should apply the sealant would be helpful.

 

Hi Mark,

Congratulations on successfully replacing the piston ring in your air compressor.

Regarding the air leak, perhaps it will help us help you if you post a photo or two of the area where you saw a few bubbles coming from an opening at the top of the ring. I can't envision the openings you are describing.

Thanks,

Don

 

Having the exact same issue; was an issue when colder, but happening more and more when it's not real cold. Will be very interested in whether the sealing of the tops will fix it. I'll try to do a soap test for bubbles (assuming it goes on). I normally only had the problem at start up; after driving for 10 minutes, I could many times shut the engine off and turn it right back on and it would be gone. How hard was it to replace the piston ring? I don't recall where the pump is.....

 

Gordon,
The pump is in front of the driver's side front wheel. You have to remove a lot of the shielding to get to it. The part supplier, Bagpippingandy.com, provides a a link with instructions for removal.

Getting the pump off was not a problem, replacing the piston ring was straight-forward. But putting the pump back on was a bear. There is very little room for hands or tools. Parts kept falling in my face. And be sure that all your hoses and clamps are accessible; I spent a frustrating half-hour or more trying to reach a clamp that kept sliding behind. Make sure you have adequate lighting.

 

Thanks! Really appreciate the tips.

So, would you suggest first replacing the seal, or look at the tops of the air spring assemblies? I would have thought it is a compressor issue (as you did). Why would one partial leak in one spring cause the error?

Anyway, please let us know how the work on the spring goes. I suspect I'll end up having to do that too.

 

A partial leak would cause the error because as it leaks down, the other side will level itself to try to accommodate. I replaced my front shocks with the Arnott units, as well as the seal kit from bagpipingandy, and so far this year have not had the issue (knock on wood). I am not sure they are serviceable.

Just throwing this out there, but I replaced both shocks - only 1 was bad, and I kept the other one (OEM) "just in case". It worked fine when I took it off. If you're interested, PM me.

 

Most times it's the shocks themselves that have deteriorated and will leak when cold. It will just get worse. The only solution is to replace or go with coilovers.

 

The easiest solution is to order up two front struts from Arnott's. before you burn out the compressor from constant cycling. When you soap up the tops of the struts under the hood and there's bubbles they are done. You can do this job yourself with a basic garage full of hand tools. The only thing I can suggest is when you replace the old strut don't hyper extend the lower a-arm and separate the ride height sensor. Wreck the ride height sensor then over to the dealer to calibrate the system after you replace the sensor. Good luck. this is very common with this vintage.

 

I by no means need to hijack this thread, but I would like to add a twist to this conversation; my entire right side just 'tanked'. Similar initial symptoms, quite close to the rather extreme drop in temperature here in Chicago. First, air suspension fault (reset with reboot-restart),....., then whole right side tanks and 'vehicle too low' message. I've taken the liberty to attach a few pics for your perusal.
I went through the PDF on air suspension and ECATS and have decided to first change the compressor valve ring. I will keep you posted:-)

By the way, the front air dampers are 2 years old from Arnott. Last service was rear tires.

Robert

 

tech tip I have done for years. to keep those 3 upper spring seats in place while you refit the compressor to the holding shafts, put a big smear of Vaseline on the post then slide the upper mounts up. they will stay in place while you fit the compressor on your back on the ground wondering why the hell you ever wanted to do this and get dirt in your eyes....

 

Also helps if you cut off a wooden broomstick or something similar, position the compressor in place on the three mounting studs and wedge the broomstick under the compressor to hold t up while installing it. Saves a lot of strain on your arm. This worked for me.

 

I find it easier to install the compressor by holding it up on the studs with one hand and with the other hand install just a nut on each stud. Then I go back and remove one nut at a time, install the upper spacer washer, spring, and lower spacer washer, then reinstall the nut. On the central end of the compressor (closest to the radiator), I also add the lower suspension bracket one end at a time. This way the compressor is held in place and you only have to fiddle with the springs and spacer washers one stud at a time. Once you have all the parts on in their correct order, you can snug the nuts till the ends of the spacer washers come into contact, then just a little tighter. The compressor will move up and down quite a bit once the spacer washer ends are in contact, so don't try to overtighten the nuts thinking the compressor shouldn't move as much. It's designed that way.

One other note for those just doing this for the first time: take care not to overtighten the air hose fitting in the compressor - several members have stripped the plastic threads in the compressor housing and ruined their day.

Cheers,

Don

 

Something I realized today after having noticed it before: When we park the car after driving it. we sometimes hear air hissing out. Today I realized that it is coming from the right side (passenger's side in US) behind the wheel. The hissing was intermittent--it would start then stop then start again. Is this normal? What is back there if the compressor is on the other side?

 

Hi Mark,

Air hissing intermittently from the front right wheel well could indicate a leaking air spring bladder. The cylindrical bladders roll down over themselves as they lose pressure, which can partially seal a leak, but when the system is repressurized while the engine is running, the bladder once again extends to its full length, reopening the leak.

Cheers,

Don