Good morning all. Looking for opinions as to the probability of a new air compressor solving the cooler weather and intermittent "air suspension fault" warning on my 04 XJ8 w/50,000 miles. I'm willing to pull the trigger if there's a certainty of eliminating this annoying problem.

The fault message has been covered in great detail throughout the forum. In most cases, people seem to have ride height issues, raising and lowering of the suspension after their cars have been idle, etc. I have none of these issues.

My car stays level, drives great, and never gives me the dreaded "ride height too low" message, whether or not the "air suspension fault" light is on. The car does not drop after sitting. The fault light appears mostly after initial start up in cold/cool weather if I don't let the car sit for a few minutes before driving away. If the fault light is on, it will stay on unless the car has been turned off for an hour or so. In these cases, it almost never reappears after restarting and driving away. Based on a lack of symptoms, I really don't believe I have one or more leaking shocks.

Will a new compressor fill the reservoir more quickly, eliminating the message trigger? Is there a clever way to disable the message? Should I just shut up, be glad I have no ride issues and live with it?

As always, your advice is appreciated.

 

I too, had no ride height or any other issues when I started to get the "yellow light" warning, and "suspension fault" message. Also the fault would disappear for a time then come back. Eventually, tired of looking at this I took it to the local main agent, who advised replacement of the compressor, which cured the fault. Compressor was replaced in November 2010.
The very short service life of these compressors is one of several issues with the car that I find very annoying as to me it indicates a cavalier attitude to durability within the Jaguar engineering team. It is durability rather than reliability that is the one issue needing urgent attention in Jaguar. Luxury cars like this should not need expensive repairs at low mileages. If Lexus can do it, so should Jaguar be capable of the same.

As regarding the detail of this particular fault, in my own view this fault appears too early, and is based on time allowed by the suspension control unit for the compressor to charge the reservoir to the correct pressure. Taking a long time indicates loss of compressor efficiency due to wear, but clearly, the compressor continues to work for a long time after the warnings start to appear thus indicating to me that the threshold time is set too low, and whilst there might be some wear, it is normal and the compressor is not yet life expired.

However, I don't suppose Jaguar are going to change anything now the X350 series cars are an obsolete model, so it is a matter for owner judgement whether to replace straightaway or wait until other symptoms appear. FWIW the cost of the compressor is not all that high as a service exchange item from Jaguar, or even new from internet suppliers, and fitting is simple, with Jaguar allowing technicians 30 minutes. Having said that the agent told me the first time can take a technician almost 4 times longer until he gets used to doing it by touch rather than sight as the unit is behind the front bumper.

The short answer is NO, unless you can get access to the source code for the suspension controller and reset the time threshold value.

 

Thanks for your response. I too have heard that, in these instances, the problem is a time-out for the reservoir to reach full pressure. My mechanic says the problem is mainly in 04 and 05 cars. I tend to laugh at that and assume that Jaguar simply changed the time-out parameters in the 06's and up as an easy way of dealing with the problem. I don't believe they changed the compressor in any material way.

 

Here is what I have learned dealing with the same problem.

You have to pay your money and take your chances.
1. Compressor may be getting weak and take a bit of time to catch up.

2. That coupled with a slow leak somewhere could combine to create your situation.

I installed a pressure gauge in the tank itself to monitor the performance of the system. It will tell you a lot. If you come out in the morning and the press is way down then you have a leak somewhere. The components are isolated at the solenoid block.

Odds are it is the pump followed by a slow leak.

Disabling the warning is a very bad idea. Pony up.

Eddie 04 XJ8 VDP

 

I can only speculate that in general, the issue involves both leaks and compressor wear. I had a shock fail at 60K which is pretty common from what I have read here. The compressor quit about 6 months before that, most likely due to wear from keeping up with the leak. I replaced the compressor when it quit and then both front shocks to solve the problem. If the system rusn 60K befiore repair, that is pretty typical for air suspension. Mercedes has air suspension as well and theirs is no better.

 

Where did you get your shocks? I just got off the phone with Arnott about their units. They don't do anything to the bilstein shock except allegedly test and do not provide the rubber bellows dust guard that it comes from the factory with. I know they are warranted but I don't want to do this twice although the rears come off easily. When your compressor went did it fail completely? I have a leaky left rear unit and think it has been working the compressor overtime.

Decisions, Decisions.


How many of you folks are running the rebuilt units?

 

I replaced my front struts with arnott's last winter. I have not had any problems. This is an industry wide problem with air suspension. They all do it. Mercedes, VW, Bentley, Rolls Royce etc... The front struts wear out, leak then start taking other components out with them. Alot of times the pump relay contacts get burned up and this causes the problem. It can be fixed easily if you remove the relay and clean the contacts. Do that first before you replace the compressor. I have a new compressor at home just in case, but cleaning the relay fixed my problem. The sooner you fix the leaks, the longer your pump will last

Justin

 

I predict that as more folks start doing coilover conversions there will be lots of used but serviceable components on Ebay. Pumps, tanks, solenoid blocks, air suspension modules, relays.

I personally will probably convert the comp and tank to an onboard air fill. Wouldn't be difficult. If I do I will post a how to.

 

The system is actually pretty simple to fix since the complex parts seem to last, the shocks and compressor are what goes, and they are fairly easy to change out. I got two front shcioks from Arnott anda compressor from JPAM in Las Vegas before Arnott had them. The compressor was about a 45 minute job and ther air springs took about an hour apiece in the driveway. No need to stress about this thing. When the system is working, it is worth the effort. The control it has over the car attitude during driving is very sophisticated and multi dimensional. I consider the cost to maintain it worthwhile.

 

I agree that the air ride is nice but I feel that the disadvantages and the possibility of being stuck out with a blown air bag override the advantages. About 4 less places to break.

Plus with the Arnott bags you get a shock that probably has at least 40k miles.

When my left rear bag went it blew up the bellows. My RV has air suspension and has been trouble free.

Plus my wife drives it mostly and she freaks when things break. She always starts bugging for a new car with a warranty.

Eddie 04 VDP

 

my advise is to check for leaks near the shocks first..the fault light in generic fault is only the tank depleation sensor...if the fault for unlevel body is triggered then u have a leak near the piping or the capping that could be a upper ring that leak due to the car sitting initually and will have to refill.once enough air has entered the cavity then the ring will seal fore inflation and the fault will disappear

 

I was replacing the air suspension compressor but when I got to the part about swapping out the old air tubes and putting them on the new compressor I broke the old air tube. Any idea where to find a replacement? Is there any other fix?

Thanks.