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Don,
Thank you much for the very comprehensive review.
My XJ6 2009 V6 3.0 liter is acting up.
Last August I replaced both front air shock absorbers (right one leaked) with new ones (Bilstein). All worked well.
About 3 weeks ago the Air Suspension Fault alert came on.
When the car is parked and shut down, after about an hour the alert does not show when I start up the car, and after tracking it several times I can say that the alert comes on after about 15 minutes drive. It can be in city traffic or cruising speed. Regardless of the driving conditions or speed...it comes up after 15 minutes.
The Jag has been to the Local Jag dealer several times. No air leaks were found; It keeps the right height level (measured before and after 24 hours); All the air was drained our of the suspension system and refilled (twice). Still not solved.
Any and all suggestions as to what can be done are welcomed.
Thank you for your kind words. I have moved your post to start your own thread.
I take it the Jaguar dealer did not find any flagged diagnostic trouble codes such as the common C2303 that so many of us have seen? Without any DTCs to help narrow down the diagnosis, you'll have to try several things to see if they work.
I would start with checking the air compressor relay, which is R1 in the Front Power Distribution Fuse Box in the forward right corner of the engine compartment near the ABS modulator that has all the pipes connected to it. Pull the relay and inspect its spade terminals and the terminals in the socket for any corrosion, and inspect the relay for any signs of overheating. If there are no obvious problems, try swapping one of the similar nearby relays for R1 and see if the problem recurs. This relay is known to fail intermittently before it fails completely.
If swapping the relays makes no difference, I would clean the grounds associated with the air suspension system, including the one behind the left headlamp that is referenced by the compressor, and the one referenced by the Air Suspension Control Module (ASM) that is either under the rear seat or under the carpet in the right rear footwell or under the passenger seat. See the Electrical Guide for details.
I have not seen corrosion on the ASM electrical connectors, but it wouldn't hurt to clean them while you have the rear seat out.
It would also be worth cleaning the electrical connectors at the valve block in the trunk under the spare wheel and sound-deadening foam cover. There is a main connector on the valve block as well as a smaller one on the pressure switch.
It would also be worth cleaning the electrical connectors for the ride height sensors (one at each rear corner and one at the front right corner).
You might call the Jaguar dealer to see if they found any DTCs when they inspected the car. In addition to C (Chassis) codes, there are U (Network) and B (Body) codes associated with the air suspension.
Interesting finding - the head mechanic at the dealer noticed some type of moisture where the sensor connects to the top of the absorber. Says it was with an "oily" texture, and the theory is that is caused the sensor to send an alert. After a first test drive ... no air suspension alert ... so there is hope :-)
No real explanation where this oily moisture is coming from or why it has started 3-4 weeks ago (car was services last September).
Will update with further details after additional test drive.
The Air Suspension Fault Alert came back again :=(
Going back to the dealer...
If you dont wanna dealerize the issue, scan it. 2303 equalls worn piston ring, and Andy has the good one. If cylinder worn replace it, also Andy. Im so glad im over this, she's a beaut now.
Thought and hoped this was over with, but the Air Suspension Fault Alert continues to come on after 10 - 15 minutes drive. I left the car with the dealer for almost two weeks. It was hooked it up to the diagnostic system and consulted online with Jag in England. The code that comes up is C2303 - Reservoir Plausibility Error. The dealer team were not successful to make it go away. Any and all thoughts and ideas are welcomed ,,, as always :-)
Thought and hoped this was over with, but the Air Suspension Fault Alert continues to come on after 10 - 15 minutes drive. I left the car with the dealer for almost two weeks. It was hooked it up to the diagnostic system and consulted online with Jag in England. The code that comes up is C2303 - Reservoir Plausibility Error. The dealer team were not successful to make it go away. Any and all thoughts and ideas are welcomed ,,, as always :-)
Hi Erez,
As romroc has noted, many of us have resolved the C2303 Reservoir Plausibilty Error code and resulting ASF by replacing the piston ring/seal in the air compressor. A few owners have also had to replace the compressor cylinder head due to excessive wear in the bore. Contact our member Andy via bagpipingandy.com for a replacement seal kit.
The C2303 code indicates that the compressor is not able to charge the system to the expected pressure in the time allotted by the Air Suspension Control Module (ASM). Possible causes include a large air leak such as a disconnected pipe or burst air spring bladder, but a worn piston ring leads to the same issue because the compressor cannot properly pressurize the system.
Any good independent mechanic or capable DIYer can replace the piston ring (and if necessary the cylinder head). Here are links to photos of the process. Note that most owners don't bother replacing the desiccant beads in the air dryer as I did, but it is a good idea to bake the beads on a cookie sheet in a 500F oven overnight to reactivate them, and also to clean all corrosion found in the air dryer, exhaust valve and high pressure relief valve.
As romroc has noted, many of us have resolved the C2303 Reservoir Plausibilty Error code and resulting ASF by replacing the piston ring/seal in the air compressor. A few owners have also had to replace the compressor cylinder head due to excessive wear in the bore. Contact our member Andy via bagpipingandy.com for a replacement seal kit.
The C2303 code indicates that the compressor is not able to charge the system to the expected pressure in the time allotted by the Air Suspension Control Module (ASM). Possible causes include a large air leak such as a disconnected pipe or burst air spring bladder, but a worn piston ring leads to the same issue because the compressor cannot properly pressurize the system.
Any good independent mechanic or capable DIYer can replace the piston ring (and if necessary the cylinder head). Here are links to photos of the process. Note that most owners don't bother replacing the desiccant beads in the air dryer as I did, but it is a good idea to bake the beads on a cookie sheet in a 500F oven overnight to reactivate them, and also to clean all corrosion found in the air dryer, exhaust valve and high pressure relief valve.
Thanks to you Don and other forum members. My pump cylinder didn't pass the fingernail/feel test so Andy to the rescue. But I'm surprised at Jag Inc. They can't figure this out? And sure, you can just order a complete new pump, but it does not come w Andy's ring, and you learn not a whole lot. During my R/T from LI NY TO VA (Jag shopping), I had no fault lights at all, haven't for a month now. Car recently sat for a day 1/2, this morning I started the cat, listening for the pump, car was a bit low, pump ran for 15 seconds, should last and last. Sure hope there is a better way out there for owners. These are terribly precious cars that have it all in aces of spades and more.
Re: replacing the piston ring/seal in the air compressor -
If as explained the compressor is not able to charge the system to the expected pressure in the time allotted by the ASM, will this not result in the car air suspension being too low? Due to lack of air? I am asking this because it does not look like the car is too low, and the dealer measured it overnight and says it is not loosing "height" .
Thanks
Erez N.
Re: replacing the piston ring/seal in the air compressor -
If as explained the compressor is not able to charge the system to the expected pressure in the time allotted by the ASM, will this not result in the car air suspension being too low? Due to lack of air? I am asking this because it does not look like the car is too low, and the dealer measured it overnight and says it is not loosing "height" .
Thanks
Erez N.
In my experience, height was OK, but fault was indicated on dash, roughened ride, handling wallowy. IMO, purchase a Jag calibrated scanner, plug in, key on, get codes. Then ask forums for help. Andys kit supports our situation. Worn piston ring might not look bad, but is critically thin. New ring/cylinder represents relief, rolaids avoidance. I smeared a thin coat of Vaseline in cylinder as an assembly/mating aid. Take note of 4 connections to pump, 2 electrical, air intake and system pressure outlet. Carefully note and photo shoot pump suspension setup. Dont get hit in the nose by falling compressor, which is sorta heavy and awkward. Wheelwell comes out easily and valence panel mostly missing on my car, which was lucky as rust took hold and it is a PITA to remove. good luck in any case. Dessicant: air dry overnight or lightly pan fry, I bought packets fron Ebay, plus pan seared. Guess what: it gets wet anyway. Cheers!
Re: replacing the piston ring/seal in the air compressor -
If as explained the compressor is not able to charge the system to the expected pressure in the time allotted by the ASM, will this not result in the car air suspension being too low? Due to lack of air? I am asking this because it does not look like the car is too low, and the dealer measured it overnight and says it is not loosing "height"
Good question, Erez,
Under normal operating conditions, the air compressor pressurizes the air reservoir, and the reservoir supplies the air springs via the valve block, so compressor operation and air spring inflation are not quite directly connected. As long as the compressor can keep sufficient pressure in the reservoir and there are no leaks in the system, the ride height may not be affected.
However, there is a pressure switch on the side of the valve block that tells the ASM when the correct pressure has been reached, and if the compressor takes longer to reach the minimum reservoir pressure than allotted by the ASM's algorithms, eventually C2303 will be flagged and the Air Suspension Fault warning will be illuminated.
For a more complete summary of the system operation, as well as links to more detailed Jaguar documents, see this post:
Just wanted to share with you that you were absolutely right. It was a compressor issue. The Dealer's head mechanic insisted that there is a "microscopic" leak from one of the suspensions and wanted to replace front suspension. I refused and took the Jag elsewhere and replaced the compressor (I will now refurbish the old compressor and keep it "in stock"). The "air suspension fault" alert turned off immediately when the new compressor started working.
Thank you for your good and helpful guidance :-)
Wishing you all Season's Greetings and a very Happy and successful 2018 !
Writing this after a very nice Christmas lunch with wife and my mother, (99). Used our X358 to pick her up from her bungalow and return in the evening. What a lovely car these are, albeit not perfect !
Glad to hear the suspension fault was sorted out. I had the same problem on my previous X350, a Sport 3 litre petrol and a new compressor cured it.That was in 2010 and the replacement compressor was still on the car when I part-exed it late last year. Early compressors were troublesome and many didn't even get through the warranty period ! Later ones were better. As regards leaks, Jaguar themselves, in their Technical Notes for the car, published late 2003 state that small leaks are to be expected in a system where the pressure in the system is at pretty high level all the time even when the car is standing.
Hi Don (and all) - great stuff! I recently fixed my issue with coming out in the morning to find it sitting on its tires... Arnott's for the win! This was months ago, just mentioning it in passing. Been great since then! Until today, the yellow air suspension fault light came on, but I cannot discern any leakage nor any noticeable lowering or unevenness.
Most of the info I've been able to find seems to deal with leaks - but is there a list that indicates what conditions will set off the yellow "air suspension fault" light? I went through all the pdf's that are attached here and in other linked posts, but not seeing it.
But hey at least the ride is nice and the level seems solid! Getting there!
Just starting on the journey of the dreaded "yellow light". In my case, it came on just as I started the car but before I backed out. No leaks noted and doesn't appear to be uneven or low.
I did have the issue a few months ago where due to one strut leaking, the car would lower itself overnight. So I replaced both fronts with Arnotts. Very good tutorial video on their website, but definitely harder (physically) than it looks. I needed a second jack to help move things around. But I digress!
Anyway, will step through this thread. I pulled and inspected R1, and while I didn't see any corrosion or evidence of overheating, when I put it back in, the light seems to have gone away. So now I am in "wait and see" mode, though now on the alert so will be paying attention to clues...
I have merged your two posts together since the forum frowns on posting about the same issue in more than one thread.
Regarding causes of the Air Suspension Fault warning lamp, the only reference I know of that lists all the possible causes of air suspension-related warnings is the Diagnostic Trouble Codes Summaries manual, which you can download here:
Note that most of the DTCs related to the air suspension begin with the letter B (Body), C (Chassis) or U (Undefined, mostly Network-related). Most generic OBDII scanners can only read the P (Powertrain) codes. To read the proprietary B, C and U codes requires a Jaguar dealer-level diagnostic system such as IDS/WDS/SDD, or a high-end third-party system such as Autoenginuity with the Jaguar enhancement.
In the column headed MIL (Malfunction Indicator Lamp or Check Engine Light), the letter Y indicates that when the associated DTC is triggered, the Check Engine Light will be illuminated. The letter M (for Message) indicates that malfunction that triggers the associated DTC will also cause a message to be displayed in the Instrument Cluster (IC), such as Air Suspension Fault. Sometimes the manual indicates that the CATS system will be indicated (as in CATS Fault).
Good to know, thanks Don. Will keep an eye on it, so far so good after reseating the relay, but after scouring the forum looks like my next best-spent time and money is on the compressor kit.
Good to know, thanks Don. Will keep an eye on it, so far so good after reseating the relay, but after scouring the forum looks like my next best-spent time and money is on the compressor kit.
If you haven't replaced the piston seal in your compressor you really should do it. But for accurately diagnosing air suspension problems it's most helpful to have access to a diagnostic system that can read the proprietary Jaguar DTCs. You might check with local independent mechanics to see if one of them has such a system.
08-13-2017 | 01:00 PM
Air Suspension Fault Alert
