Hello everyone, I'm kind of new to the forums. I have a 06 XJ8 base model that I got from my mother. The car is in really good shape for it's age. It has just over 82000 miles on the odometer. The problem I'm having is after the car sat for around a month, I was out of town for an extended period; the battery died and needed replacing. While sitting over that period the suspension lost its height down to the lowest allowable limit. When I started the car and ran it for a while the rears pumped back up but, the fronts won't come back up. The suspension has lost height after sitting for more than a few days in the past but, it always pumped back up with no problem. Any suggestions would be greatly appreciated.

 

You could try removing battery cables and touching them together for a few mins
and then if possible drive it for up to to 20mins

 

The air shocks are often considered to be wear parts.
The rears seem to outlast the fronts.
Braking shifts the cars weight forward.

 

I understand they're wear and tear parts but, both fronts going at the same time. In the past after sitting for a few or more days and loosing pressure they always pumped back up. The rears pumped back up with no problem. The car did sit a lot longer this time and killed the battery. So it sit awhile with no power for any of the systems. I'm gonna do some leak testing to see if that's the issue.

 

Drive the car and see if it comes up, have this happen once in a while after working on the car and jacking it up. Jag says 25mph, but usually once I get moving (10-15mph) it will start coming up. Are you getting warning messages? If not I can almost guarantee once you get the car moving it will come up.

 

Yes, I'm getting the suspension too low and suspension fault lights. I've gotten those same 2 faults in the past but, the car always raises itself back up. I haven't tried to drive it yet. I'll give that a try and see what happens. Thanks

 

Without a reader to see the codes from the Air Suspension Module, anything you do is guessing. I will tell you that a dead battery will confuse the hell out of every system on the car, from the air suspension to the parking brake to the cruise control. These things are ultra-sensitive to low voltage, even a tenth of a volt low. I'll also say that once the Air Suspension Module throws a code and lights a message on the dash, it stops trying. There will be no more air suspension commands from the unit until the car is shut off and restarted.

 

My advice is to first get a reader to see the specific codes. My 04 XJ8 did this same kind of thing in the rear of the the vehicle and it turned out I had a popped air suspension bag. You could also reset the car's computer by disconnecting the battery for a few minutes to see if the fault lights come back.