Hello all,
Got in my Jag the other day and the “Suspension Fault” light came on. I drove it home about 15 miles away and the car drove fine. I parked it overnight and the next time i started it up the message was gone. Drove around for a few days and still no message. Today the message returned, drove it home turned the car off, locked the doors, unlocked the doors and started it back up and no message..
any advise would be greatly appreciated.. BTW The battery is only 18 months old.
TIA
2012 XJL 67,000 miles

 

Without getting the error codes we having nothing to work with?
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Historical, like what Clubairth1 says, codes are key and unfortunately, you need something like the SDD to give you the code. A cheapy code reader is not going to get into the system far enough to tell you what you need to know.

With that being said, I have seen this problem a few times here and it always seemed to get fixed by replacing the right front strut. Not sure if you want to take a chance on just replacing a part and seeing if that fixes it or spending some money to get confirmation as to what the problem is.

 

Thank you for the info. My indy shop pulled a code.. C1A20-64 from an OBDII scanner.. Maybe that helps?

 

HIstorical, that code indicates that the reservoir is filling too slowly when the pump is running. So, that means you have one of the following things going on:

Signal plausibility failure
Gallery pipe air leak
Compressor fault
Reservoir pipe air leak
Reservoir air leak
Intake filter blocked/restricted
Intake pipe blocked/restricted
Air suspension intake silencer blocked/restricted
Corner valve stuck open

So, the first thing I would do is let the car sit for say 24 hours (atleast overnight), then toss a bunch of weight into the rear of the car to make the system have to adjust for the weight there. Now with the trunk open and the plate over the spare tire removed, start the car. Walk back to the trunk and listen for any air leak. You can try using a spray bottle with some soapy water (1 teaspoon of dish soap to a 32 ounce bottle) and spray the tubing to see if you see any bubbles forming. But, to get this problem, odds are, what you are going to see is the going in and then making a sudden direction change. That will tell ou that you are close. You can then run your fingers near the tubing and see if you feel an air. From there, you can let the car level itself out and then you are going to need to start removing the tubes mentioned above and blowing through them. That will point you to a blocked line.

 

That’s great information and insight on what maybe the issue. I will work on that this weekend.
Thank you so much for this valuable info

 

Since you do have that code it is very common that the compressor needs a "ring job"!
We are lucky Bagpipingandy's has a compressor Repair Kit. He has made the piston ring out of an improved material too.

Take a look and I have installed one of these and it will solve the problem. However that was just the beginning of my troubles and repairs with that car!
Compressor Rebuild Kit
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I may be wrong, but I thought the rebuild kit referenced was for the Wabco compressors. The X351 uses an AMK compressor. I have experienced the same code twice. The first time I bought an aftermarket pump that cured the issue, then failed in a year. They have a lifetime warranty, so sent me a new one. THAT one failed after a year. I sourced a used AMK (OEM) (low miles, for cheap) and it has been fine since. The failure point has been the exhaust valve. In the first case it was shorted, in the second case it was sticking. That was consistent with the "venting air too slowly" message. FWIW, the Foxwell scanner (530 is what I have) with the JLR software reads all the BCM and PCM codes, does OBD II, and most hardware calibrations, resets, and initializations.

 

Good to know and sorry for the bad info!
Lucky for me my X351 air suspension has had no problems....yet?
The prior model of XJ had so many air suspension problems Jaguar must have taken them to heart and upgraded things for the X351. They dropped the front air springs too so maybe that was the difference that made it more reliable?

Just glad I am no longer fighting air suspension issues on an older X350!
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The irony is that they are now reliable, AND very accessible, since moving to the "boot".If it IS the compressor, there are three nuts (it hangs on studs) securing the compressor, and three torx screws securing the rear trunk fascia. There are 2 electrical connectors, a large hose, and a small hose. Remember, it is a high pressure system. Before doing anything with the hoses, know which are pressure lines and vent the pressure before tampering with the line. The scanners that have JLR software (mine is a Foxwell) do have modules to deflate the system, then to re-initialize it (if needed) after the replacement.

 

Thermo,
Just a quick follow up,
I took the steps you set forth and did not hear any air leak. My car is level and balanced. I wound up disconnecting the negative battery terminal for a bit and reconnected. I have not had any Suspension fault code since. Ill continue to monitor.
Thank you

 

Thermo,
I believe the compressor needs replacing. Looks like an easy swap. I called the local Jag dealer near me and they want a ridiculous $2800 just for the compressor plus about $500 for labor.. Any suggestions on a good replacement brand that’s not as much as my mortgage payment?
After replacing does the car need any computer recalibrating?
Thank you

 

I have been down this road recently.. I replaced it with an Arnott compressor, which was cheaper, AND had a lifetime warranty. It failed after a year, and they replaced it. The replacement failed in a year, and I found a fair number of used OEM compressors on ebay, made a $100.00 offer on one, installed it, and the car is again fine. If you go with a non "Jaguar OEM", you can find an AMK brand, which is the OEM supplier, at a bit more than Suncore or Arnott , but FAR less that Jaguar. Five hundred for installation? I guess that's why I do not go the the dealer. It is a simple one hour job. You just need to know what you are doing, as it is high pressure, and you need to either use software to release it, or VERY CAREFULLY bleed off the pressure at the fittings.

 

Thank you for your informative response. Unfortunately I don’t have the software to bleed off the pressure so if I back off the fitting VERY slowly will the pressure release?
Also once I install the new compressor will the lines re-pressurize on there own?
Thank you

 

HIstorical, check ebay. you can find them a lot cheaper than $2800. Yes, you should be able to loosen a fitting to release the air. Granted, on second thought, it seems to me there was some button combo you could push that would depressurize the system that did not involve the use of SDD. Let me check into that. I may be wrong.

 

Thank you Thermo, any info on releasing the pressure would be greatly appreciated.

 

Historical, let me get off of these 12 hour days i have been on and then I will give you what I can find.

 

No rush, thank you

 

Maybe i can help meanwhile: By checking the principle of operation from Service & Repair manual (available from Sticky section of this forum), inside of valve block there are valves for each rear shocks and air resevoir. The shocks are pressured by air resevoir and once desired ride level are reached the valves are closed. Resevoir are filled by compressor and once desired pressure are reached, the valve are closed. By this, there should not be pressure at all in compressor or its piping to the valve blog above it, as long as there are no need to raise vehicle. So chancing compressor should not need release any pressure from system at all. However, i would disconnect the battery before starting this job. Without power no measurements or opening any valves are not possible, so the pressure should stay in shocks and resevoir.

The description of valve block also confirms that when non-powered the valves are closed:

 

Thank you sir, That was very helpful information.
Much appreciated!