Well, I've got some strange behavior in my '05 VDP and I thought someone who understands how the air suspension system works might have some insight...as she's basically stuck in the driveway.

I put on a full set of the new Arnott's air shocks, as it has gotten cold my stock car was dropping in the front every night. I rebuilt the pump and that was a help, but it was still taking too long to pump up.

*on a side note, I really like the ride, got rid of all the jitters and bumps that the bilsteins had - feels like a young buck again!

I did notice with the new arnott's as it got into the below freezing zone that one back corner of the car would drop overnight, but pump itself right back up once started.

Once it dropped into single digit temps - the back end, on both sides, has dropped to the bump stops. Low rider. I now get the 'vehicle too low' and 'air suspension fault' lights.

I thought I wasn't hearing the pump, maybe frozen or relay went out, but a couple days ago I started it again and watched this:

The pump ran, I saw the rear pump up to ride height, then within a minute or so, I heard air venting from the rear - the rear dropped on both sides about half way. It stopped, then it did it again! Dropping all the way to the bottom.

I've got a friend upgrading a laptop for me so I can run a clone scanner, but I won't have it until this weekend at least.

I can come up with a bunch of ideas, but I don't know how the system really works, so it's all just WAG's.


*I did recall that I forgot to pull the battery cable when I did the rear shock install. I thought this might have messed up the ride height, but it was doing fine until it got really cold.

Click any ideas from anyone?

Strange!

 

Take a look at this description Ross -

jaghelp.com: XJ ? Vehicle Dynamic Suspension

Hope it helps.

 

+1 on the link above

Also I know this sounds weird but a rule that I've learned over the years as a mechanic is... whatever the problem is, check the battery first. Haha sounds funny but i'm sure a lot of forum members can understand why. After your battery is ok then its time for some reading. Here are some air suspension bathroom reading material:

jaghelp.com: How to change the air suspension compressor on your Jaguar XJ

jaghelp.com: Super XJ air suspension C2302: an odd leak

jaghelp.com: XJ ? Vehicle Dynamic Suspension

jaghelp.com: How to change the front air springs (suspension struts) on your Jaguar XJ

If your car sits overnight and always seems to lose air in the same corner then you most likely have a leak in the respective circuit. If your problem is more random then I would be inclined to think that your problem lies in something common to all four circuits, like the compressor (you mentioned you rebuilt it, in my experience that doesn't always work), the module (to this day I only seen one bad and that was because the dumas* owner hooked up the battery backwards), or a sensor (I replaced about 3 or 4 in my career as a Jag tech). If I remember correctly there is only one front sensor in your car, and is used to calculate the geometry of the other side, might be the cause of your fault.

Keep us posted!

 

Check your ride level sensors that are attached behind the wheel between the A-arm and the chassis. Sometimes when installing new struts it's possible to pull down on the suspension enough to pull them apart. It happened to me on the front. The metal shaft pulled out of the lower end of the plastic pivoting fitting. Just epoxied the shaft back in and wrapped a wire tie around to hold it until dry.

 

Thanks Ed, I'll dig thru the snow and see what I can see...it is a bit warmer this weekend.

I'm still reading, but here is the link to the official Jaguar training on the system:

http://www.mediafire.com/view/7rdkgg...on_Section.pdf


I just printed it out. My other thought is that the back shock that was dropping down each night when it wasn't too cold, is not even worse when it's single digit cold, exacerbating the problem.

I'll look at the ride height sensors and pull some trunk bits out and search for leaks.

 

The ride height sensors are clearly visible. You may want to check the air fitting for leaks or tightness on the top of the strut. I would use a 12 mm flare nut wrench instead of an open-end wrench to check for snugness. If you have a leaky struct you, they are lifetime warrantied. Good luck it 0 F in Milwaukee this morning.

 

Thanks to kbeachy for letting me borrow his laptop with a working clone! (I got the version for windows 7 and have not gotten it to work).

Wow, SDD isn't exactly user friendly software, I forgot how far we've come in interfaces.


I did get it to pull the codes and these are the 3 that related to the air suspension:

C2302 leveling plausibility error
C2303 reservoir plausibility error
B2810 air suspension vent solenoid - circuit failure


*the vent solenoid sounds interesting - like maybe it became disconnected? anyone know offhand where it's located- with the air pump or with the tank?

ugh, this has been a trial!

 

For the B2810 code the vent solenoid is on the compressor. If you disconnected the electrical connector even with the car off that code will be set.

Clear the code and make sure the connector is fully seated and see if that code comes back.

Sounds like you have an air leak or you need a new piston ring.

 

Thanks abonano, I did rebuild the compressor several weeks before doing the new arnotts, so that would have set it!

Yes, sounds like I have an air leak somewhere.

How do you clear the codes with the software? it wasn't obvious to my quick look.

 

I don't have experience with SDD.

I would kindly ask if you installed the replacement piston ring in correctly?

I installed mine backwards and set a plausibility error code. I realized my error, reinstalled the piston ring the correct way and zero issues since.

You can remove the air line from the compressor and let it run and try to keep your finger on it. If you can keep your finger over the port for more than 5-10 seconds this might be a tell tale sign.

 

Thanks, I'm pretty sure I did, as I double checked the piston ring. It also worked great for the several weeks until I did the arnotts. (cut the 'pump up time' in a quarter).

Nice weather finally, I'll check for air leaks.

 

Well I got it fixed today. Took the whole trunk insides out to check out the lines - found one of them wasn't fully seated in the new fittings and had blown out.

I checked the other one and found it was leaking some air if I wiggled it and I was able to pull it all the way out.

I called Arnott tech line, and they were very helpful, willing to send me some new Voss fittings (those are the compression fittings you put the air line into). He even emailed me a pdf of how they go together so I could see.

However, after looking over the diagram and looking at the lines, I (hopefully) figured out the problem.

The jaguar air lines are formed at the ends- they curve. I had cut them off at the old fittings and then trimmed them again with a hose cutter before installing, this didn't leave much more than a half inch or less before the curve in the air line, which prevented it from fully seating in the new fittings.
After looking it over I was able to free up enough line to make me comfortable, then I just cut the whole elbow curve off each air line. They seated much further down into the fittings.
Took it for an hour drive today and no leaks!

I'm going to get back with the tech at arnott and let him know, I mentioned the elbow in the line but he didn't think it was a problem - anyone got a picture of the curve in the line?
I think that will show them what is going on, more than just describing it on the phone.


oh, if this helps someone else:

the air fittings are 4mm voss fittings.
you can buy them at tractor trailer supply places, any place that does big rig or others using lots of air compression and such.
Tech also informed me that O'Reilleys has them: part K2261 but are usually not stocked, but they can order them.



The air ride is back!

 

Glad to hear you got it fixed.