Hi lukie,

Most of the diagnostic trouble codes that can be triggered by the air suspension fall into the C (Chassis), B (Body) and U (Network) categories, so they cannot be read by a standard OBDII scanner that can only read P (Powertrain) codes. Do you have access to a system that can read the proprietary Jaguar codes? That may be the fastest route toward diagnosing your issues.

Cheers,

Don

 

HiDon B, i was begining to think that, just looking to try and find one that isnt going to bust the bank, pulling my hair out, replaced compressor and relay but still seems to sit high enough for quite a while the comes on, the you just cant get it of untill youleave her for about 10/20 mins.
Thanks for the info, any more dont hesetate.

 

Hi lukie,

I would suggest finding a good independent shop that specializes in Jaguar and asking if they can scan proprietary Jaguar codes on your year and model, which I now realize you haven't shared with us. It's a good idea to add the year, model and engine info to your signature line so others don't have to ask in order to give you the most accurate replies.

By the way, for less than the cost of an air compressor you might have been able to acquire a system capable of reading the Jaguar codes yourself, so please don't throw any more money at parts until you've fully diagnosed the cause of the misbehavior.

Cheers,

Don

 

Which relay is #4 in trunk fuse box. I can’t find a diagram?

 

Hi redxk8,

What is the year, model and engine of your Jaguar? The location of relay #4 varies by model and year. It's helpful if you edit your signature to include this information so it appears in all of your posts.

Cheers,

Don

 

I’m sorry, i thought i had done this. I’ll get to it asap, thanks
Have interesting out come on suspension system. I’ll share in the new future as soon as I get caught up from returning to my home.
Rich

 

Hi Rich!

Did you figure out which relay is #4? You still haven't told us the year, model and engine of your Jaguar...

Cheers,

Don

 

I've been trawling through the many threads etc in an attempt to fix my 2006 x350 air suspension, last year I replaced 2 front air shocks, about two weeks ago I replaced the air compressor after a persistent c2302 code,and today I replaced the rear airshocks, as the rear drivers side kept losing air over night and rear end of car would drop to the ground. Each time I Starr the engine whin a mile of driving I get air suspension fault on dash and yellow light,and c2302 levelling plausibility error code, in live data of my scanner if the system when the error case comes on it shows damper firm error also. The car will not raise in height whilst parked with or without engine on, whether the car is slightly low at rear or at too low at rear. The car will only raise in height once over 25mph for the air compressor to cut in and raise it. Once raised and within a mile the c2302 code comes on. Could this be the non serviceable PCB relay R7 of the rear power distribution fuse box being faulty although the rear footwear and grab handle courtesy lamps still work. Or something to do with the valve block/solenoid under spare wheel?? Or something else?? I'm all out of ideas and almost at the point of ripping anything air suspension off the car and going to coil overs, this is not something I want to do though but getting so frustrated with its complexities. I'm sure there's someone on here cleverer than I that can shed light onto this for me
many thanks

Mark

 

Hi Mark,

I know how frustrating these air suspension issues can be.

My first suspicion regarding your C2302 code would be an air leak. A common leak point after compressor replacement is the air hose fitting at the compressor. If it is over-tightened, the plastic will crack and leak. You can spritz soapy water on the air fittings at the compressor, on the tops of all four air springs, and on the fittings on the valve block and reservoir. Bubbles indicate a leak. Just take care to avoid wetting any of the electrical connectors.

The default mode for the dampers/shock absorbers is Firm, so if there is a fault in the system your ride will be firm. Are you also receiving the CATS FAULT warning in the instrument cluster? Check all the electrical connectors on the tops of the dampers as a starting point. The wires are very thin and the pins in the electrical connectors are very fine and easily damaged.

Cheers,

Don

 

Hi Don,

No cats errors dash only says air suspension fault with yellow light on, when I hook up diagnostics it then shows the c2302 levelling plausibility error, and in the live data damper firm error = yes. I've already sprayed with soapy water the valve block in the boot and all is OK, as are the air connections to the tops of each shock, I haven't done the soapy water on the air compressor yet. But does the air compressor have to be running in order to check fir leaks at the compressors pipework or not? Also would any of the 5 solenoids in the boot valve block cause this issue if one were not operating correctly or at all? The live data shows voltage and the solenoids open and closed on the air shocks. Also if it were due to compressor pipe leaking would that only affect the rear of the car? (Only the rear sinks down over night prior to the rear air shocks replacement that I did today-but I have a funny feeling in the morning the rear would have sunk again to most if the way down or all the way down)
I wondered about the non serviceable boot relay in my eallier post only because the system only raises the suspension at plus 25mph when compressor cuts in, and it raises it quite quickly then.

Mark

 

Also had C2303 before replacing compressor too

Mark

 

CORRECTION that should say had C2302 and NOT C2303 code before replacing air compressor. Additionally as an update this morning after replacing rear shocks yesterday the rear was all the way down to the ground again and front at normal height with vehicle too low warning, this was only raised by the compressor when car got to plus 25mph

 

The compressor only runs at over 25mph, or when first starting the car before you move. the minimum speed before the compressor runs is a noise perception thing by Jaguar, they don't want the compressor noise to impinge on the passenger experience, or whatever.

 

The compressor doesn't run at first start up so I need to get it to plus 25mph in order to raise the rear end which sinks down to the bump stops overnight, once upto height from compressor running and normally within the first mile or so of driving the c2302 error appears. I don't know why the rear sinks down all the way overnight and why the error code appears, I have new shocks all round now and a new Compressor, I can't find any leaks, would a faulty boot valve block under the spare wheel be slowly venting air from the rear all the time? The front stays at normal height. I'm so frustrated with this air system

Mark

 

The compressor should run shortly after the engine is started if you leave the transmission in Park. Try starting the engine and leaving the trans in Park for 2 or 3 minutes to see if the compressor will start. Sometimes the ASM will not start the compressor if fault codes are stored. Can your scan tool read Network (U-prefix) codes?

The valve block has no vent itself. The only intentional vent in the entire system is the exhaust solenoid vent valve on the compressor. Since your compressor is new, we wouldn't expect your valve to be leaking.

It is possible that the valves for the rear air springs in the valve block could be stuck partially open, allowing pressure to vent into the rest of the system and out of the exhaust valve when it opens to backflow dried air through the desiccant bed, but an air leak somewhere in your rear system seems more likely. It would be worth contacting lcmjaguar to see if he is still willing to loan his pressure test gauge set, or you can build your own after his example, as I did. The gauges will quickly tell you if there is a leak at one or more corners.

https://www.jaguarforums.com/forum/x...2/#post1062760

Cheers,

Don

 

Hi Don

Thanks for your reply and help, the compressor does not cut in during park after starting engine engineer 15 minutes, literally only at plus 25mph. I know not so helpful but not sure if it reads u codes, I can delete the stored c2302 code after restarting engine with code tool.
If the valves for the rear airsprings inside the valve block where stuck partially open what would be the end result of this valve sticking? Would it cause my problem of rear suspension bottoming out overnight? Just to add some more info I had a leak in the boot area about a year ago which during bad weather totally submerged the valve block and the bottom of the boot fusebox, I removed fusebox and dried it out and dried out valve block electrical connectors with hairdryer. Rear shocks are brand new yesterday and behave like the originals did in terms of overnight bottoming out.

Kind regards

Mark

 

It's difficult to say, because it seems as though it would depend on what other valves were open through which the rear air spring pressure could escape into other parts of the system. But the only point at which pressure is supposed to leave the system is the exhaust valve on the compressor. Since only your rear springs are deflating, the most likely cause is a leak somewhere at the rear. Another possibility is that the ASM is mistakenly lowering the rear end overnight in an attempt the level the vehicle.

That could be an important part of the story that you left out!

Was the rear end lowering prior to this event, or only afterward?

Cheers,

Don

 

Only lowering afterwards but sometime after the event,, air shocks as I said are new, no leaks on air connections to shocks and the rear lowered to ground when old shocks were installed also, no air leaks around valve block connections, when/if the rear shocks vent air or air I lost through the system somehow from the rear shocks is it possible the air goes out of the shock, through the pipe work and is allowed to escape through the valve block partially stuck valves and out the vent exhaust of compressor. I'm no expert and far from it hence my questions in trying to understand the issue and possibilities

Mark

 

Off the top of my head, it would take a very particular combination of valve positions in the valve block, and the compressor exhaust valve opening, for air to escape from the rear air springs and not the front air springs.

It doesn't seem like it could be a ride-height sensor issue since both rear corners have their own sensors and both would have to be telling the ASM that the suspension was too high for the ASM to intentionally lower the rear.

If you haven't done so already, the post at the link below is worth studying, along with the documents it links to (a few of the links are now dead but I think the most important ones are still good). It will help you understand the system and its operation.

Air Suspension & ECATS System Summary: Components & Operation

Cheers,

Don

 

Just a point which might not have been mentioned.
Assume you parked and locked your car with all the air pumped up. Then suspension goes down overnight. Merely unlocking the car (no engine, no compressor) should pump the suspension up from the reservoir near the valve block. It only has the capacity to do this once.

If it doesn't, I would opine that the reservoir is not holding air (obviously!), and I can only imagine the associated reservoir valve is leaking. Or something (just to cover myself). So other valves might be leaking too.
(sometimes my shocks go down, but my reservoir never does in weeks and unlocking will pump it up. Which is why I don't like opening my hangar-queen unnecessarily)

I don't see too many suspicions placed on the valve block, but air valves holding air "long term" (or overnight!) strikes me as a weak point. It's not a NASA cleanroom, a bit of dust through a not-so-good filter and you're stuffed, I imagine.

Also, the compressor should run with the engine started and the car not moved. Not sure of the delay until this happens. If it doesn't, not sure how to tell if there's an electronics fault. My hoofy method would be a battery disconnect fancily known as a cold reset.