I'm having issues making my big cat unpredictable in this very cold winter. If I have no leaks, get the car to perfect ride height in a warm garage, and disconnect the ECATS module behind the seat will the air struts hold their height or will they release for some reason?
I have an 04 VDP that is giving me fits in this sub freezing Ohio winter. I have 4 newer Arnotts and a rebuilt pump. I think I've got solenoids in the valve block sticking/freezing. Any morning it's less than 20 degrees F my shocks are a dice roll. Back end up too high, all shocks too firm, or (today's final straw) the driver side two inches too high while the passenger side was fine. I've tried battery resets already.
I have no leaks, but just ordered the Arnott coil over conversion. I'm just trying to make the handling as predictable as possible until the coils arrive. There's more snow in the forecast. Thanks in advance.

 

Yes, you can pull the ASM fuse and in theory (if there are no leaks) the car will remain at the last height set--barring any height changes due to the air temp change. If you get it to ride height in a 40F garage and then park it outside overnight at 0F, it will probably sink down some because air pressure in the springs will decrease.

 

Thanks! I can just pull the under hood relay or do I need to unplug the ECATS module behind the seat?

 

The underhood relay controls the compressor, not the air suspension module, To disable ASM without removing the seat, there are two fuses you can pull in the rear fuse box, but I don't know which ones on an '04. I'm not sure it's the same ones as my '07, as somewhere in those years was a set of wiring changes, and I'm not sure what changed or when or where. If the seat is out, unplug the connector on the ASM that's towards the right side of the car; that's the one that carries battery, switch power, and ground.

 

Hi Andrew,

The ASM that wfooshee referred to is the Air Suspension Control Module behind the rear seat, which controls both the air suspension and the ECATS adaptive damping. You can learn more about the system at this link:

Air Suspension & ECATS System Summary: Components & Operation

To determine which fuses and relays provide power to various parts of the system, you can review the wiring diagrams in the manual this link:

Jaguar X350 Electrical Guide 2004

Your description of your symptoms makes me wonder if your system has accumulated enough condensed water that it is freezing inside the valve block, preventing the solenoids from operating properly. The molecular seive desiccant beads in the air dryer cylinder that is part of the air compressor assembly can only adsorb a limited volume of moisture before some of the moisture makes its way into the rest of the system. Over time, quite a lot of water can accumulate.

Cheers,

Don

 

Pull fuse number 52 (yellow 20 amp) in the rear box (next to battery)

 

I just came back, thinking about the moisture issue that Don B mentioned. I know when I pulled my compressor out to install the new ring and seals from the rebuild kit by bagpipingandy, I found that the desiccant cylinder was absolutely saturated, with water sitting in there. Water even dripped out when I unfastened the compressor's output hose. I ordered a package of new desiccant beads and refilled the dryer cylinder with those.

If your compressor's been around a while, and these certainly have, then the dryer has been overwhelmed by now and is not doing its job. The rebuild kit doesn't include desiccant, just the piston ring and o-ring for the cylinder. That kit was about 50 bucks, and a package of beads was less the 15, which is certainly less than the several hundred for a replacement compressor.

If that service gets done, the system will eventually get dried out as air moves in and out over time, and these symptoms might simply go away.

 

I was planning on revisiting the air suspension in the summer. I love air when it's working.
I think you're all right about the moisture. The coils will get me through the winter and will be a nice safety net if the air ever loses its mind again.
Thanks all for the advice. I will pull the car into the bay tonight and pull the fuse.