Hi all.

First of all, I should mention that I've been driving on my full-sized spare for a few months after getting a flat tire (back right tire). I didn't notice when I put it on, but the spare tire was a slightly smaller tire than the other 3, which explains why I was getting some traction control intervention when making hard left turns sometimes (I figure the TCM thought I was getting wheelspin due to the tire size difference).

Over the Memorial Day weekend, I decided to plasti-dip my wheels. I jacked up the car, one side at a time, and took the wheels off for painting. While I was at it, I changed out the back right wheel for the one with the correct sized tire.

Well, since then, I've been getting the air suspension fault message after driving with a bit. It goes away after power-cycling the car, but comes back after a while. When parked, it does look like the back right is sitting a little low.

After replacing two of the air struts last summer (not the back right one), I'm now kicking myself for not doing the coilover conversion right away.

What I'm wondering is, since I changed the tire size on that back right wheel to the larger tire size, is it possible that it's 'confusing' the air suspension after driving with the smaller tire for the past few months, and the car thinks there's a problem with the ride height on that side? Is there a way to 'reset' the suspension's memory, so to speak? That corner looks a tad low, it's not bottomed out or obviously blown (like the two I replaced last year were).

It all seems a bit too coincidental that the error comes right after jacking the car up and replacing that wheel for it to be a typical air suspension problem, unless jacking it up was the straw that broke the camel's back...

BTW, the wheels came out nice:

 

May I suggest you get the fault codes read. Too many people rush to replace expensive parts and then find out the fault is still there. Apart from the Arnot steel coil conversion, they also do air springs with new air diaphragms fitted. These units are made by Bilstein, and the shock part lasts far longer than the air spring diaphragm so is a good option rather than swapping out the whole system to steel coils.

 

Yeah, I've replaced two of the air springs with Arnott units already. I'm just wondering if something else is up because this happened immediately after I changed the tire size.

I'm assuming that I would need a Jaguar tech to read the fault codes? I have an OBD reader but it doesn't report any faults.

 

Hi Anticitizen,

Yes, reading the air suspension codes requires a dealer-level system such as JLR SDD (or, possibly, a high-end computer based independent system such as Autoenginuity with the Jaguar module/interface).

The correlation of the suspension problem and the wheel swap certainly seems like a clue. Was the car jacked up for an extended period (overnight, for example)? I'm wondering if the air suspension control module may have re-leveled the car while you had it jacked up, so now it thinks the new lower setting is correct for the right rear corner...

Cheers,

Don

 

Don, it was jacked up for maybe 2 - 3 hours while I painted several coats of plasti-dip to the wheels (and let dry). I have two floor jacks, so I pulled off two wheels at a time, left side first, then right. Of course, the 'problem corner' is the only one in which I replaced the tire with a slightly larger one (though it matches the other three now).

I just did a battery disconnect just a bit ago, to see if it isn't just 'confused' and in need of some sort of reset. I'll see if it behaves on my drive to work tomorrow morning.

 

Hi Anticitzen,

The rear corners each have their own height sensor - if things are better tomorrow, it might be worth inspecting the right sensor to be sure the electrical connector is clean and fully seated and the articulated arm on the sensor is intact and connected at both ends and the middle. It seems possible that something has happened to the sensor, possibly related to jacking up that corner.

You don't mention hearing the sound of air leaking from the rear air shock, and I can't think of any way you could reasonably cause an air leak by repacing a wheel/tire... (just thinking out loud).

Please keep us informed!

Cheers,

Don

 

Thanks. If problems persist, I will check out the sensor. I have not heard any strange air noises.

 

Well, no luck. The message came on again during my drive home from work. I took it to a parking lot, rolled down the windows, and drove over some speed bumps, and sure enough, I could hear the air hiss. Must be a small leak, because after I did the battery reset, it looked like it had lifted the corner to the correct height. I guess it just can't maintain it during driving, which is why the fault message comes up after driving for a bit.

I suppose it was close to failure, and jacking the car up was the straw that broke the camel's back. Grr! Now I have to decide whether to replace it or go with the conversion, which sucks because I've already replaced two air springs already. Should I replace just the one, knowing the remaining one will fail at some point, and probably the compressor too, or just shell out the cash for the conversion?

Anybody have any comfort suspension rear air springs left over from a conversion that they'd like to give me a great deal on?

 

My advice is to replace the air spring that has failed, (assuming it has), with a good used or Arnott with new diaphragm. This then leaves just the one original. There are new-old stock units on the internet, I bought four Comforts just before Christmas for £800 the four incl postage. The weak part of the spring is te diaphragm, the damper part lasts a very long time, mainly because the rod seal is not exposed to road water. salt and other detritus

 

Hi Anticitizen,

Before you commit to replace the air spring/shock, it might be worth trying to locate the leak using a spray bottle filled with soapy water. Disconnect the CATS electrical connector from the top of the shock and apply a piece of duct tape over the electrical connector, then wet the bases of the air hose and pressure valve brass fittings and watch for any bubbles that would indicate a leak. It may be that you just need to replace the O-rings on those fittings.

If you don't find a leak around the fittings, then the leak probably is from the air spring bladder, and unfortunately we have not yet found a source for DIY replacement bladders (Arnotts claims to use bladders made by Goodyear).

Please keep us informed.

Cheers,

Don

 

As don suggests chasing and locating the leak is first step
You want to know you are replacing the correct part before you buy expensive replacements

Chase the system using a spray bottle with soapy water

Areas to check
1. Air Compessor line (on the compressor)
2. Air compressor vent (make sure its not stuck or partally open all the time)
3. Valve block and tank in the boot
4. Air fittings on the air springs

It may be the leak is internal on spring or in the lines
In this case you need to make up some block off fittings

You can get them from enzed or the like

A good start is to remove the air line from the springs
On the spring fit a short tube and tyre valve
Block off the line with a blocking push on tube fitting
Now you can pump up each spring with a tyre pump and nothing should leak.

If that's ok you dont need a spring replacement and you can start working your way back checking the lines to the valve block next, valve block and tank then finally the line to the compressor

If you find its a line you can just run a new one with push on tube or cut out the bad section and add new line and joiners.

PS if you search my posts I post a how to some time ago on these fittings

Cheers
34by151

 

Thanks guys, I will do some diagnosing tomorrow. Maybe it's possible that I knocked something awry at the compressor when I was pulling out and replacing the spare wheel.

 

Hi Anticitizen,

The compressor is mounted inside the front bumper at the left corner, but the air reservoir and valve block are in the trunk and you very well may have disturbed an air line at the valve block or between the valve block and reservoir.

Let us know what you find.

Cheers,

Don

 

Well, I tried finding a leak, but with no conclusive findings.

I give up. That's three air suspension failures in one year. I'm tired of the recurring orange eye. I've already replaced two air shocks, and I'm not going to replace the third, only to have the fourth one eventually fail as well, and then the pump, etc.

Therefore, I just bit the bullet and ordered the Strutmasters conversion kit from Amazon at $1200. I will part out and sell the two practically new Arnott air springs I installed, the yet-to-fail OEM one, the compressor, tank, etc. I figure I can make a good chunk of the money back, or even a profit. Used compressors go for $300 on Ebay, reservoirs for $100 or so, and Arnott springs for $400+. The control module looks like it sells for $150ish.

Compressor - $300
Reservoir - $100
Springs x3 (assuming I can get $350 for each) - $1050
Control module - $150

Total: $1600, meaning I could walk away $400 richer after sweating under the car and scraping my knuckles doing the conversion. That makes the conversion a no-brainer to my mind, and I'll never have to see that $#@&'n Air Suspension Fault message again. I honestly wish I had done the coilover conversion at the first sign of suspension trouble instead of replacing parts for a flawed system one by one.

If anyone wants to make an offer for the parts, let me know. The parts won't come in for a few business days, so I probably won't have the conversion done until next weekend.