Hello, I'm new to this site and just found my first Jaguar and absolutely love this car. It's a 2008 XJ8 with 58k miles in very nice condition. From what I've read, the air suspension system on these cars are prone to problems and this one is no exception. Usually the front suspension will deflate overnight and most of the time it will air back up after a few minutes when started. Sometimes however, it won't air up when started. It then gives me a "Vehicle Too Low" message and after driving it triggers a "Air Suspension Fault" message. If I stop and restart the car a couple of times, the system wakes up and raises the front end. Now all of a sudden, it's working fine and has stayed inflated even after sitting for several days. I've driven it a couple hundred miles in the last few days and it's been working perfectly.
I don't trust it so I had the car scanned this morning and it pulled up the code: C2302 - Leveling plausibility error. Because the system has been functioning normal for the last week, he recommended that the code be cleared and drive it for a week or so to see if it malfunctions again and sets another code.
Any thoughts or ideas?
Thanks,
1Carguy

 

Depending on your location, the colder it gets, the more likely you are to have issues

 

Possible fault with a level sensor or associated wiring.

 

I would also favour the cold issue.
The colder, the more frequent it will be.
There may be a temperature threshold effect, when the rubber inside the spring isn't soft enough to accomodate the dilatation of the materials, so that leaks appear.
If it is too cold with the "vehicle too low" on the dashboard, the compressor may give up after a few unsuccessful attempts to raise the car, and then you get the "air suspension fault".

Depending on your car and status of its air suspension ECM (yes, I know, looks strange but not all vehicles behave the same, so maybe a different programming) you may however succeed to raise the car once the engine has become sufficiently warm (if you have the patience to do it at idle for 20 minutes) so that the front springs (usually they are the culprits) become also warm enough not to leak anymore. That is what I observed on mine, meaning that the default code stored did not prohibit the compressor to continue working. But that would be a temporary solution.

The permanent solution if you don't want to be stuck in winter is to replace your front air springs (first do a leak search to confirm they are leaking).
Another possible culprit is the compressor itself. The bagpipingandy kit is then the usual solution (much less costly than new springs).
But if the issue seems to be cured by a warmer engine, it's more probably the springs themselves, as the compressor location will not allow meaningful heating by the engine.

Plenty of threads on this issue, make a research

 

Hi 1carguy,

Wingrider, meirion1 and paydase have already given you great replies, but to add just a little more information, the most common cause of your symptoms is a leak in the top seal of one of your front air springs. In colder temps (say 40F or colder), the aluminum top plate of the shock absorber contracts, and the rubber top seal, which wraps around the top plate, loses its seal because it has hardened with age. You can see the edge of the top seals around the perimeter of the circular depressions in the tops of your front air spring/shock absorbers. The electrical connector in the nut in the center is for the ECATS adaptive damping system. The top seal rubber is often a faded and dirty red, pink or orange color.

To date, the only reliable solution is to replace the front air spring/shock absorber units, either with OEM Bilsteins or rebuilt OEM units (RMT is one rebuilder). Converting to non-OEM units typically means the ECATS functionality will be lost.

paydase's suggestion of rebuilding your compressor with bagpipingandy's kit will help your compressor re-pressurize the system more quickly, so it's definitely worth doing. While you have the compressor apart, clean the rust and debris off of the leaf valve and from inside the exhaust vent solenoid valve, and bake the desiccant beads in a 500F oven overnight to dry them out.

The air suspension system is explained here:

Air Suspension & ECATS System Summary: Components & Operation

Cheers,

Don

 

Thanks for the input. It's been cold here at night so maybe the weather has effected the air suspension. Yesterday it took about 20 minutes and several restarts to before it finally came to life and pumped up. I think my first step will be to search for any obvious leaks with a soap solution. I have read that access to the compressor is quite a job, so I'm not looking forward to tearing this apart. Wish me luck!
Also, is it safe to use a floor jack or stands under this car? I don't want to damage any undercarriage body seams or components by jacking it up or using jack stands in the wrong place. Is the regular jack points the best place to use a floor jack?

 

I use two floor jacks, one on each side under the jacking points then raise one side

a bit then the other until it's high enough to place floor stands next to the jacks then

lower body onto the stands and leave the jacks in place.