Thanks for replying, Xag.

Like I mentioned before, I did hear the compressor come on right after finishing the repair and restarting the car. It sounded louder than usual, but it refilled the shocks within 2 minutes, after which I heard the familiar blow-off sound. Since then I haven't heard the compressor or blow-off at all. Oftentimes (but not always) before the repair, I would hear the blow off after parking and locking the car or sometimes (but not always) when coming to a stop on the street, but nothing since Saturday. I've ordered a new OEM relay, but I'm not holding my breath. I'm planning to change my sway bar bushings soon, so I guess I'll tinker with the compressor again then, if the situation doesn't improve.

I'll try disconnecting the CATS and report back. I wonder if the springs could somehow be over-inflated, but like I said, ride height seems to be same.

 

I just disconnected the CATS connectors on top of the shocks, and went for a drive. After about 30 seconds I had to stop and reconnect them. Man, that was terrible. Thankfully, my ride does not degrade to that level.

I listened again for the compressor to kick on or the air to let out, but still nothing. Ride height is same as usual.

 

I just conducted a test. I slowly unscrewed the air hose from the front passenger shock. Within a few minutes, all the air escaped and that corner was low on top of the tire. I screwed the hose back in, and started the car. I drove around the garage slowly for a minute, then stopped (ride was HORRIBLE). As soon as I did, I could hear the compressor come on, and within 120 seconds, the low corner rose. However, it did not rise all the way level with the rest of the wheels. Instead, the entire car seemed to level itself somewhere between rock bottom and the standard height. I took it for a spin around the neighborhood. The ride quality was even worse than when the ASF comes on, but not quite as bad as when the CATS was disconnected. Even still, within 10 minutes, the ASF returned, but this time with no discernible difference in ride quality.

I drove back to the garage and tried restarting the car multiple times, trying to get the suspension back up to standard height. It would not budge. I thought to myself "great, now I've really effed myself." So in frustration, I disconnected the battery and performed a hard reset. And while I was back there, I removed the Blower relay and swapped it with the Air Suspension relay. I turn the car back on, and BAM, the compressor kicks on again and successfully raises the car to standard height, followed by the vent of air. I drive it around the garage and the suspension feels absolutely wonderful.

I suppose my test is telling me that the compressor is working just fine, otherwise I believe the ASF would appear within the first few minutes after starting the car.

Perhaps the title of this thread should be edited to include the Air Suspension issues.

 

I made an appointment with the local dealer to get the codes read on Monday. We all have to pay the piper sometime.

 

After 3 hours and $150, the dealer said the valve block assembly needs replacing and gave me the following codes:
C2303 - Reservoir plausibility error
C2302 - Levelling plausibility error
U2516 - Air Suspension compressor relay circuit failure
U2516 - Air suspension module bus off

Apparently these codes have been in storage for a while, so they cleared them, took it for another drive and then scanned again. This time they all returned except for C2303. They investigated further and found the valve block had a small leak and wanted $1500 to fix it. Ha!

Any thoughts?

 

Buy a used valve block and replace it yourself in 30 minutes. It's a piece of cake, have a look under the spare and see for yourself. I bought a spare block for €75.

Guus

 

There are some on ebay going for around $125, but they're from high mileage cars and I don't want them to go bad on me again right away. Besides, I'm not entirely convinced that's the entire issue. The dealer did not exactly instill me with confidence in their diagnosis. I've been discussing this with Bagpipingandy and he's not sure its a valve block issue either. I'm having trouble finding another instance where it was the valve block that needed replacing.

 

A thought just occurred to me...lets say it is indeed the valve block that's leaking. The brass fittings on the air hoses would be the most likely place to leak, correct? If I inspect the area with soapy water, perhaps I can locate the leak(s) and seal it without having to replace the entire assembly.

 

Ok, I tought they really found a leak in the valve block for sure.

I've re-read the thread and see you mention a few things. Rattling, ASF message and a harsh ride. I'm interested in the harsh ride, is it still there even after changing both front shocks? You notice both a smooth and a harsh ride?

Guus

 

Yeah I'm afraid this thread became a catch-all for all my various suspension issues.

The dealer tech said it was indeed a leak in the valve block, but I don't trust them as far as I can throw them, so I take their advice with a grain of salt.

I notice the ride becomes very harsh after the ASF message appears. Before, it's as smooth as it can be, but I've had this persistent knocking/clunking/rattling noise for a long time now, and I've almost got it. First, the lower control arm bushings were replaced, which helped, but soon the noise was back and it was angry at me. Next, replacing the front shocks permanently cured about 50% of the noise. Then I replaced the sway bar endlinks. That cured another 25%. This past weekend, I replaced the sway bar bushings (see https://www.jaguarforums.com/forum/x...cement-124412/ ), and that seems to have finally gotten rid of the noise once and for all, but if you read that thread, you'll notice I'm in the middle of another issue that occurred as a result of the bushing replacement. So, in regards to my noisy suspension, victory is within my reach.

Once that's done, then I can turn my full attention to tracking down this supposed leak in the valve block and finally curing my Air Suspension issues.

 

Let us know when you continue your search. Somehow I don't see the relation between the ASF message and the ride getting firm. You don't have access to the SDD software?

Guus

 

No I'm afraid I don't. As I understand, the shocks go into "hard mode" when the ASF appears.

 

No they don't. I've had the ASF message several times when my compressor was bad and the ride stayed the same. With the SDD we could see what happens by running the data logger. You can log when the CATS switches on and off.

Guus

 

That's interesting info, because I'm pretty sure the manual claims it does go into hard mode.

 

Just to chime in, when I was having an occasional ASF on cold days last winter when our compressor could not recharge the system within the alloted run time, our suspension would suddenly become very "loose," bouncing around like there were no shock absorbers/dampers in the suspension.

I haven't studied all the potential causes of the ASF warning, but perhaps it can be triggered by faults that lead to very different default behaviors?

Cheers,

Don

 

I think you need to do some research and google the codes.

I believe that the best place to start is with the codes and it's interesting that the c2303 did not return so you can discount the compressor.

C2302 - Levelling plausibility error

Investigate level sensor fault (eg bent bracket but they can fail also)

U2516 - Air Suspension compressor relay circuit failure

Change relevant relay (easy)

U2516 - Air suspension module bus off (CAN circuit comms fault)

Pinpoint tests (not so easy)

One other point is that I don't believe the valve block leak somehow but bear in mind

that you can get an internal leak in the valve block between solenoids.

Good luck

 

Sorry to hear about all this craziness

 

To add to meirion1's excellent advice, the Jaguar X350 Diagnostic Trouble Codes are explained in fairly good detail in the Workshop Manual, which can be downloaded in six sections from the X350 'HOW TO' quick links thread on the home page of this X350 forum. C codes are in the Chassis section, P codes are in the Powertrain section, B codes are in the Body section, and U codes are primarily in the Electrical section. The Workshop Manual code descriptions are a better reference than some online sources that may give code explanations that apply to other auto makes that are different from Jaguar explanations.

Cheers,

Don

 

Analyzing codes is a good thing but you have to relate them to the individual problems that you have. If the harsh ride would be like CATS switched on and of I could imagine the ASM being bad. But if the harsh ride is not CATS like harsh but it is intermittent, I'm a little puzzled what could cause it.

Guus

 

AIR SUSPENSION FAULT UPDATE: The night before last, I decided to conduct leak tests on my compressor hoses and the valve block hoses. No leaks. However, for the heck of it, I unplugged the two electrical connections on the valve block and inspected them. They seemed clean, so I plugged them back in. Three drive cycles of at least 17 miles each have passed since then with no sign of the ASF message, whereas before it would appear after 10 mins every single time no matter what. I'm hesitant to claim victory, but its an encouraging development to say the least.