in this case of no faults i would recommend a dealer scan in case the hand held is not reading all faults, this is common.

im not sure of a leak just yet but maybe electrical - 1st guess,

Don, whats the unit on the jag's shocks used to stiffen them, maybe something to do with this

get the fault codes 1st

regards

Andy

 

Hi XJRLondon2004,

As Andy mentions, it does sound as though you may be having a problem with ECATS, which is the newer "Adaptive Damping" system. It is Jaguar's adaptation of the ECAS system by Wabco, the OEM that supplies most of the air suspension to Jaguar (everything but the air springs/dampers themselves, which are made by Bilstein).

The way ECATS works is to modulate the damping rate of each shock depending on driving conditions. The default mode of the shocks, with no electric signal applied, is "Firm." To soften the ride, the Air Suspension Control Module (ASM) sends a pulsed electrical signal to the CATS solenoid in the top of each shock, which modulates the valving to change the damping characteristic to "Soft."

Cambo351 shows the 5V 400Hz 1ms pulse-width signal on a scope in this post:

https://www.jaguarforums.com/forum/x...76/#post544336


Regarding Diagnostic Trouble Codes (DTCs), your bluetooth code scanner can probably only read "P" or "Powertrain" codes (and possibly not all of those). The suspension codes are mostly "C" or "Chassis" codes, and to read them (along with the "B" or "Body" codes and "U" or "Undefined" codes (mostly Network-related codes)), you need a scanner that can read Jaguar proprietary codes, such as the dealer-level Jaguar Land Rover Symptom-Driven Diagnostics (JLR SDD), AutoEnginuity with the add-on Jaguar module, or another high-end system. It is likely that you have suspension-related DTCs logged but your scanner cannot read them.

Please let us know what the dealer finds.

Cheers,

Don

 

Hi, thanks so much for the comments, ok so the Jag is at the dealer, I am waiting to hear from them and will let you know. They told me that they will use special powder to check if there are any air leaks, and also they will check some other issues. I hope they do find the problem....

 

Don that is a very interesting thread, I am assuming, that the defualt ride "FIRM" is probably the same as when you put it in sport mode. When I get the fault, the ride is not FIRM, it is like driving on the wheels without tyres
Lets see what they find out,

Many thanks for your comments

 

If the car does not sink down at any time or does not give the "too low" error then their are no leaks, the fault codes will check the operation of the electrical system and let you know if their is a faulty or problem areas or components

regards

Andy

 

Mine is throwing codes constantly for the active damper circuits. It will set codes for all four corners at seemingly random times. Sometimes it claims there is a short to ground and other times there is a short to voltage (circuit high, circuit low, etc.) Very frustrating... not even sure where to start with the diagnostic process. I suppose I'll back probe all four dampers and use the scope to watch the signal as I wiggle harnesses. I'm guessing something is chaffed.

 

I have installed two new Arnott front air shocks and the Bagpipe Andy compressor r&r kit. Still getting air suspension fault after 7-10 minutes of driving. Rear shocks seem fine with no sagging at any corner. Could relay be the issue? Also, where is the best place to get relays in the US? I have checked many online sites but cannot find the brown 40 amp one for air compressor. Thanks!

 

Hi all while we are on the subject of suspension

My car seems to let of a puff of air after a long drive like releasing air from the suspension reservoir is this normal

 

If the compressor runs will not be the relay, what are the fault codes, the fault code will tell us why the light comes on, it could be too many things to guess.

Best regards

Andy

 

Hi,
If this puff of air is when the compressor stops running this is fine, it is releasing pressure from the airline.
if the puff of air is after you park and lock the car this too is normal and it is just adjusting to either being not perfectly level or weight being removed or added to the car.

if it sinks to the bump stops with this puff of air that is not normal, but I guess it is not sinking down it is just making minor adjustments releasing a little air.

Regards

Andy

 

The ASM also clears out the moisture trap using a "puff" of air. It does it regularly on my car, generally after a run.

 

Thanks Andy and Fraser she is normal yippee

Not used to a jaguar with nothing to do except enjoy

Aha she is due for a service and pads and rotors I knew there must have been something LOL

 

Hi , ok so they called yesterday, the did a 24h test, and it turned out to be the right side SHOCK that is leaking a bit of air, so I am assuming there must be some kind of a seal. But they quoted 1100 pounds for the job and I said no thanks. Because it doesn't happen often, and I don't think it makes sense to change just one. It is as if once you start changing things in the suspension syste, as I did with the air compressor, then it is on to the next WEAK spot somewhere. And so on, and so on The only thing I don't understand, is I never got the TOO LOW message, and why the air suspension fault comes on when driving , can it really be because of a leaking shock?

 

I'm pretty sure that if you are getting air suspension fault, it's because the compressor is running too much trying to keep up with a leak somewhere. Someone else can confirm, as I'm not the expert. I just finished replacing the left front air spring on my '04 XJ8 with a remanufactured Arnott (still has CATS in place). Now my suspension is golden... even at 28 degrees F this morning it was perfect.

 

Yes, you will get the fault with a leaking shock. The module that controls the system knows how long and how often the compressor needs to run in a standard system, so when it registers that it has to run a little longer or often in a leaking system it will trigger a code.

The thinking is that the sooner a leak or fault is found, the fewer the components that will need to be replaced. Ignore a leak, the compressor eventually pays the price.

When I had a leak in a front shock, it only leaked on very cold mornings, and only very slightly, if I drove it when it was that cold it would trigger a fault. If I drove it on a warm day, it would never trigger a fault. Cold temps expose the leak, and in the short run warm temps will "cure" it, but it will only get worse over time.

Fortunately, replacements or refurbed units are now a lot less spendy.

 

When I look at the cutaway diagram of the Bilstein air spring in the Technical Notes, it is obvious there is a large complex moulded rubber seal at the top as part of the top mount. We know the air pressure in these air springs is quite high in normal running, and gets verry high when cars get onto full bump, like about 20 Bar odd, which is nearly 300 psi. Also the US gets much colder winters than we do here in the UK.

I'm thinking that in the very cold conditions, this rubber moulding shrinks slightly, but also will get hard and unable to mould itself to the securing steel housing when air pressure gets up against it. So air will be able to leak out and cause all the awful symptoms currently being experienced.

 

Yes you are right, and I did get the fault on cold days only. Today in London is 18 degrees, and I did a drive to Guildford and back with the car full of people, and NO FAULT. But I did notice that when I come to a full stop at a ligt, sometimes, the nose will just lift up.