Howdy folks. I've been reading thread after thread about my issues and have come to the conclusion that I know enough to know that I need to know a lot more. I picked up my 04 XJ8 with 53k miles on Sat, 14 JUN. On Monday afternoon, the CATS System Fault appeared very briefly. So quick that I was barely able to read it before it disappeared. It then came one again and I got my phone out to snap a pic and it was gone by the time I tapped the shutter icon. I was "fortunate" enough for it to come on again shortly thereafter for an extended period of time and I was able to obtain several photos of it. The ride of the car seemed rather rough, but I didn't pay it much mind until then.

Then, the Air Suspension Fault started flashing back and forth with the CATS fault. I found that the car has no air in the system and the compressor is not running, therefore the air tank is not filling and the system is not getting any air... Last night (Monday) I removed the spare tire and the foam cover to see if there was anything obvious I could see/hear. I did not see anything and did not hear the compressor with the car running or not, when sport mode was engaged and disengaged, etc. I found all three fuse boxes and checked everything that had to do with the suspension and none of the fuses were fouled. The #4 relay under the hood (bonnet for those who refer to it in that manner [I watch A LOT of Top Gear and Eddie Izzard and have picked up on the differing terms]) fuse block is one of the culprits I’ve read about and intend to replace as soon as I can. Additionally, my mechanic explained to me that the front shocks (dampers) have been replaced. I checked the wire connections on top and the pins inside; all was in order.

Prior to this, I went to my local auto parts store to have the codes read and they only came up with the standard P1111, which as I’ve read is, essentially, rubbish. I plan to go to the local Jag dealer if the #4 relay doesn’t remedy the issue. I may go anyway as it’s probably the best choice. But, being stubborn as I am, I feel I need to try this first. It’s not TOO costly and might just do it. When I removed the spare I also disconnected the NEG battery cable for a bit. I reconnected and, as I thought, the faults were not appearing, but, of course, the CATS came back this morning and the ride was still VERY rough so the suspension was not getting any air and it’s only a matter of time before the fault appears again. With all this being said, does anyone know which thread is the most solid for both of my issues as I feel they are separate, but could possibly be related? I’m at a loss as to what to do or where to go other than what I’ve already reported here.

Now that that’s all been said, I have a couple more minor issues that I am hoping to find common fixes to. The first is regarding the right side front seat (the passenger’s seat here in the U.S.). The lumbar control will go forward (pressing on the lumbar region more), but when pressed to release the pressure, it does nothing. I checked all the fuses related to the FR seat and found none in need of replacing. Any thoughts? Secondly, and I know sounds VERY bizarre, I was listening to my chosen morning radio show on my way to work and to help clear the moisture on the rear window, I switched on the Rear Defroster(RD) and the radio immediately went to a high degree of static with the radio program barely audible in the background. When I switched off the RD, the static went away. I did this a couple more times to verify the relation and it was most definitely verified. Once again, any thoughts? Thanks!!!

 

When you get a CATS fault, the system will not switch the dampers to 'Soft' so you will get a hard ride as the default is 'Hard'.

CATS is just a system to switch dampers between hard and soft settings depending on what the car is doing, so when you brake, the fronts are set to 'Hard' until braking ceases. CATS gets information from the ECU, and ABS modules, plus two accelerometers, one front, one back. Although it is integrated into the ASM, it has no input into the air spring height setting. If your also getting an air suspension fault, it could be the compressor is worn out. Normally the piston seal wears out, and our member on here, bagpipingandy, makes and sells a seal kit for DIYers. If you're not a DIYer, you can buy compressors on the internet at reasonable prices.

However, get the fault codes read. A C2303 is normally the compressor.

 

Thanks for the prompt reply. I was not able to locate a relay locally. The best I could do is have one ordered and it’ll be here tomorrow. Meanwhile, I looked at the box again and saw that there was an identical relay right next to the #4 so I changed them out to see what would happen. All of the Auto part stores I phoned called it a flasher relay so I did the due diligence and turned on my flashers and removed the #4. The flashers worked fine. I removed the identical relay and placed it in the #4 slot and the one from #4 into the other’s spot. I did not notice anything at all. While on my run to pick up lunch, I had to brake hard and the CATS fault appeared briefly again. The ride is still very hard as well.

I am VERY MUCH a DIYer. In addition to other BBC America shows I mentioned, Wheeler Dealers with Mike Brewer and Edd China is one I never miss. There was one episode I recall when they were working on a Disco (Land Rover Discovery for the other U.S folks here) and the compressor piston rings were the issue and the refurb of them was pretty straight forward and seems like something I could tackle quite easily. However, I am not sure it’s the piston rings as I feel I would hear the compressor running and I don’t even hear that. With that being in the mix, what can I do to “jump start” the compressor to try to learn if it’s in the electrics or if it’s in the compressor? Also, what should the proper multi-meter readings be on each pin on the two plugs going in?

On a brighter note, I purchased it from a dealer AS-IS (that’s not the bright side) and picked up the title today which has the previous owner’s name and address one it. I intend to find and ring him to learn what I can from what he knows of it… Wish me luck!!!

 

If you end up needing to replace the compressor, PM me. I recently gutted the air suspension and replaced it with the coilover shocks, and have a compressor in good working order that I'll sell for lower than the ebay price, with free shipping.

(I also have three good shocks - front left OEM, and right front and left rear Arnott units with only a year's use in them)

 

I will MOST DEF keep that in mind. My mechanic informed me that the front shocks were new and looked great. Now, on to the BAD news. I just spoke with the previous owner. The first thing he said was, “Get rid of it as soon as you can”. He followed that juicy little nugget with, “It was in the shop more than it was in my driveway”. So, this dandy Jag that I had the best feeling about out of all three is looking like I got GOT. He was able to give me the info of his previous mechanics that he used and the authority to sue his name when I speak to them.

So, it looks like I am TOTALLY screwed. The dealership won’t even consider a return. It was sold AS-IS and I can opt for a warranty, but there will be deductibles and shared labor/part costs, (hardly a “warranty” IMHO) so I cannot decide which is going to be the least costly. I think I’m going to list it online and get my $$ back out of it…

I am DEEPLY saddened by this as this was the one…

 

If I'm not mistaken, its actually the #1 relay under the bonnet.

 

Hi Ragman,

Sorry you're experiencing these issues with your Jag. You've already received some very good advice, most importantly that you need to have the fault codes scanned by the dealer or a good independent Jag mechanic with the proper scanning equipment to read the proprietary Jaguar codes. Without the codes, you have no idea whether the problem is serious or minor.

You mention listening in the trunk for the compressor to run - in case you are not yet aware, the compressor is at the front of the car, inside the bumper cover / wheel arch liner at the left corner. Unless your compressor motor is fried (unlikely), the most you will likely need to do to the compressor is replace the piston ring, which is easy. Below are links to photos showing the process (I replaced the desiccant in the air dryer also, but that isn't strictly necessary):

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page


Please have the Jaguar codes scanned and then report back to us and we'll try to help.


Regarding the other issues, please start new, individual threads for the lumbar and radio static issue, and we'll try to help with those also. It's just best for the forum to keep threads focused by subject when possible.


Cheers,


Don

 

Don et all,
Thanks for the info and pics. I just spoke with the mechanic who the previous owner used religiously. He concurred that it was in the shop a great deal of the time for one thing or another. Apparently, an O2 Sensor fault was the main culprit and several high end shops were not able to track it down and one little shop, the one I just spoke with, was able to find and remedy it for good. He recalled the car well and said that the compressor was in need of replacing.
Additionally, I did not know the location of the compressor and assumed it was in the trunk(boot) with the other gear. Thank you for that VERY valuable info. That’s just like me at times, spouting off without completely researching it first. With that in mind, I will be going through the manual tonight and seeing what I can see and hearing what I can hear in the location mentioned. If it’s running and there is no pressure, I’m certain that the rebuild will be in order, but if it’s not even running, I have to determine where the stoppage is, if there is one, or if it’s the compressor itself not running at all. I like to fiddle with things and I don’t see this being much different, but I will have the manual and all of your input to aid in my endeavor. I DO NOT want to let this car go… But, I have to be realistic... I don't want to find myself in a ten foot hole with a two foot ladder.

 

This video will be a big help in getting to the air compressor:


Honestly, if the air compressor was the only negative thing that mechanic had to say about it, I'd say you came away well - sounds like the previous owner took care of a lot of the maintenance so you won't have to!

 

I'm absolutely frustrated, aggravated, agitated, and any other ‘ted I can't think of at the moment. I got home and got the front wheel off. I located the compressor and found the two wire harness connections to it. The Green and red arrows in the pic I snagged from the rebuild tutorial that Don B posted. I had my wife in the car turning the key to position I, position II, and then starting, activating Sport Mode, deactivating Sport Mode, turning off the engine, and all other things I could think of in between that I can't recall now if there are any. This was done with the harnesses connected and disconnected with a multi-meter on the leads. The Compressor motor (red arrow) gave a range of readings of .07-.13v. The Exhaust valve harness (green arrow) gave .00 all the way through. So it appears that the compressor is getting juice, but I don't know if the fluctuating voltage is causing an issue or if the compressor is just not any good at all. About the only way to tell is to get another, known working, compressor and hook it up and see if it works, but that's a costly experiment, to say the least.

I have to add that I did not feel the compressor engage at all when we went through the range with the connections in tact. I may very well take the offer presented previously just to try to rule it out. If it STILL doesn't work, then I can, at least, sell the known working one for what I paid and have a pretty good idea that mine is still good, but then I have to find what the actual culprit is… Calling that a daunting task is a gentle euphemism.

I am open to any thoughts, ideas, etc. I hope that my explanations have not left any gaps of untested areas. If there are more tests that I can do, please fill me in. Thanks again!!!


Respects,
Jason

 

Hi

The compressor will only run if the engine is running. It runs until the reservoir is charged, or stops after 2 minutes to let it cool down. If it fails to charge the compressor in the 2 minutes then Fault Code C2303 is logged, plus a message "air suspension fault". As I understand it, there is a relay to switch the amps to the compressor. This is a very reliable charging system and used by Audi and others. The compressor is Wabco, and common to several cars. Our member, bagpipingandy, who makes the seal kit first started making them for Audi compressors, and then found out it is the same for the Jaguar. The compressor is not intended to run continuously, as it would soon burn out. It only runs when the reservoir drops below a certain pressure. If there are any leaks, it will run much more frequently and wear out prematurely. However, with any system using compressed air, there will be very minor leaks, just like one gets with auto air con systems. The compressor will handle these but not big ones.


As regards the CATS fault, it does an electrical continuity check on each of the shocks. If any is open circuit, (i.e. there seems to be no connection to that shock), it logs a fault code and message. This is separate from an air suspension fault.

Could I suggest you disconnect each shock in turn and reconnect as it might be as simple as a slightly corroded connection. If you open the hood, you'll see the top of the shock with a wiring connection. It is very simple to unplug and replug, but make sure the plug goes in correctly and doesn't bend the pins. It will also be worth checking these wiring looms for integrity, one may have go damaged at some time in the past.

My feeling is your car doesn't have a major fault, just a couple of niggling ones that need a knowledgeable Jaguar mechanic to fix. FWIW, I had to replace a compressor a few months after buying my car in 2010.

 

Thanks for the input. The shocks on the front are new and I have checked them a few times and they all appear clean and properly connected. I was under the cal feeling the compressor when she was going through all the ranges, including when it was running, and it did not start up at all. I should have added that it's all the way down on all four wheels as well. I went through every possible position with the ignition with the wires connected and it never started up. And went through every possible position with the wires disconnected checking them with a multi-meter to determine if the compressor itself was getting power. As far as I can tell, it is, but the voltage seemed to vary which is what I'm most curious about at the moment. After speaking with the previous owner, he implored me to not go to the Jag dealer here as they could not even remedy an O2 sensor issue four times along with other issues he faced while owning it. I hope that helps with the troubleshooting a bit more. Thanks again!

 

Hi Jason,

Off the top of my head, the compressor should start running shortly after the engine is started. It will then run for a maximum of 120 seconds, at which time it will be shut off in order to prevent overheating of the motor and piston ring/cylinder. The compressor will not run with the key in positions I or II. I don't believe Sport mode will affect the air compressor behavior in any way (Sport mode has more to do with transmission behavior, holding gears longer before upshifts, for example). After the compressor shuts down after startup, it will not run again until the car reaches 25 mph, and if the car slows to below 18 mph, it will be shut off again, even if the system is not fully pressurized (this is to prevent the occupants of the passenger compartment from having to endure the noise of the running compressor, which is apparently swamped by road noise at speeds above 25 mph, according to the Jaguar engineers).

However, if you have driven the car recently, or started the car recently, the system may be adequately pressurized and the compressor may not be started at all when you re-start the engine. Best to conduct your test after the car has been sitting overnight so that some pressure is lost and the compressor will be required to run to recharge the system.

I'm wondering if you have the scale of your meter set so your voltage readings are 1/100th of the actual voltages (for example, do you have it set to measure up to 1000VDC)? If your meter allows for it, try selecting a lower range, such as 20VDC. Is your interpretation that you were measuring 7 to 13 volts DC at the compressor motor electrical connector? Did you take your measurements with the electrical connector disconnected, measuring at the connector on the harness side, not the one on the motor? If your measurements of 0.07 - 0.13VDC are accurate, you are probably just measuring DC leakage or eddy currents in the system (Ross can tell us the correct term).

The exhaust valve should receive 0V at any time when the compressor is running to pressurize the system, such as at startup. If the exhaust valve connector had 12V on it, the valve would open and all the pressure would escape and your system would never pressurize. The exhaust valve opens only at times when the compressor is not needed, such as when the system pressure needs to be reduced, or after engine shutdown, when the valve opens to allow dry system air to backflow through the desiccant bed to carry away some of the condensed moisture and partially reactivate the desiccant.

To satisfy your curiosity about the compressor, it would be worth trying this:

After the car has been sitting overnight, before starting the car for the first time of the day, position yourself with your hand safely positioned on the compressor, then have your wife start the car. You should be able to hear/feel the compressor start up within a few seconds after startup. If the compressor doesn't start within 20 seconds, you may need to connect 12V directly to the compressor motor connection to confirm that the motor runs.

Having said all of that, based on your symptoms, I'm not sure your compressor is the problem (or the primary problem). If your suspension feels hard, it has air pressure, so the compressor must be pressurizing the system. If that were not the case, your car would be sitting very low and would ride like a boat bouncing on waves.

Before you spend too much time and become even more frustrated, I would highly recommend that you have the car scanned for codes.

Cheers,

Don

 

Don,
Thanks for bringing to light what I had failed to mention previously. The car had been sitting for a time after I got home from work and had plenty of time to release any air if there were any in it before I did the tests, but I'm going to get up 15 mins early tomorrow morning and test again before my morning shower. The car sits very low and the stance has not changed at all since I got it on Saturday. And, your analogy of the boat on waves is spot on. So much so that when I take turns at speed that are on rough roads, the tires leave the ground and I can feel the car "skip" sideways and audible chirps can be heard from the tires when they reconnect with the pavement.
I had the tester at 20v DC and did my tests on the end of the harness connector that actually connects with the compressor itself. I did not want to pierce the wires outside coating. I did the tests through all the ranges just to rule out as much as I can. I am aware of the shift point extension that Sport Mode provides, but if I didn't try, then I'd wonder "what if?" and I didn't want that looming over my head.
Having the exhaust be at .00 was not surprising as there was no pressure to exhaust...
I am in agreement that it may not be the compressor (alone), but I am at a loss as to what it could be or what/where to test next. Thank you again for aiding me in this venture that is quickly becoming a quest! lol

Just for GP, I just went out and tried again just now (9:00 PM EST). I was under the car and had my daughter start it and I held it for 120 seconds, (that's two minutes for those using the metric system J/K!), and it did not kick on at all. I have the Legends L2 Air Ride suspension system on my Harley and I'm quite certain I would know if the compressor was running or not and this was most definitely not.

 

As pointed out the relay for the air compressor is R1 in the fuse box in the engine bay. The relay is orange.

Try swapping out the relay with another orange relay.

If you find another color relay in the R1 slot (like black) someone swapped out the original orange relay. It may be a FordMoCo relay (my opinion - this 40A relay is a lesser quality relay then the Jaguar orange 40A relay.

Also, test the R1 relay - could be faulty - I had a parasitic battery drain issue and my compressor relay (black FordMoCo) was not working correctly.

I believe there is a fuse in the boot fuse box for the air compressor as well (could be wrong - long day) check the electrical manual and make sure the fuse is good.

As far as CATS is concerned - once a fault is detected - even if the fault is rectified - the code(s) must be reset by the dealer or someone that has Jaguar level software like WDS...

I'm pretty sure the same is the case with the air suspension system.

Just my $0.02

 

[QUOTE=ragman1171;997573]The car sits very low and the stance has not changed at all since I got it on Saturday. And, your analogy of the boat on waves is spot on. So much so that when I take turns at speed that are on rough roads, the tires leave the ground and I can feel the car "skip" sideways and audible chirps can be heard from the tires when they reconnect with the pavement.[QUOTE]

Hi Jason,

Thank you for providing this additional information. I'm sorry to say that it does sound as though your air suspension has suffered a complete loss of pressure. Driving the car in this condition poses safety risks to you and your loved ones, not to mention the risk of irreversible damage to the air bladders in the shocks and other components.

The owner's manual warns that if the message, 'AIR SUSPENSION FAULT' is displayed at any time, drive with caution and have the vehicle checked by a dealer at the earliest opportunity. Your car is exhibiting symptoms of no air pressure in the suspension system, so please take this seriously.

Given that you have not yet been able to measure anything close to 12V at the compressor electrical harness, I do think it would be worth checking in the morning after the car has been sitting overnight. It can take several hours for the pressure in the system to diminish. The ASM does check periodically to re-level the vehicle, and if necessary, it opens the exhaust valve to release some pressure, but if I recall, it only does so every 24 hours.

If you don't get 12V on the compressor harness connector during the first two minutes after startup tomorrow morning, suspect the air suspension relay (as XJ8JR correctly noted, it's Relay 1 in the Front Power Distribution Fuse Box at the front right corner of the engine bay). Hopefully the new relay you have on order will resolve the issue.

I really think you should have a serious conversation with the dealer. He knowingly sold you a car with a serious safety issue...

Please keep us informed.

Don

 

You hit the nail on the head with the black relay. It didn't say Ford MoCo, but only had a the following markings ++12203 1C. I've added a pic as well. I will check another orange fuse right now and report my findings in this reply. As for the fuses, I've been through all of them that had anything to do with the suspension, air compressor, etc and found none that were blown.


Verdict of the test. There were three other orange relays in the box and I tried each one. I had my wife start the car and I timed it for one minute each time the engine was started and the compressor did not run on any of them. I can guess with 99.9% certainty that it's not the relay. I a seeing a replacement compressor in my future..


Unless I get more ideas of testing... I'm all ears at this point as I have nothing else I can think of.


On an unrelated note, the lumbar button on the right side seat not going back when the button is pushed and the defroster causing the static in the radio... Does anyone have any thoughts on it as it seems I've come to an impasse with the air ride...

 

Before you ever considered a new compressor you should run 12V directly to the electrical connector at the compressor to see if the motor runs. If so, you know your problem is upstream somewhere. You really need to get the codes read before you spend any money!!!!!! This forum is full of accounts from owners who replaced compressors or air struts and still had the same malfunction. Learn from their expensive mistakes!


As I mentioned earlier, please start new threads for each of these issues so this thread doesn't get off track. It helps keep the forum more useful when threads are focused on one issue each. I and others will be happy to try to help. Thanks!

Please let us know if the compressor motor runs when you apply 12V, and what codes are stored in the computer.

Cheers,

Don

 

Don,
Well spoken and duly noted. I will refrain from the other issues in this thread until I can determine a cause and remedy for my suspension issues and will then address the others in future threads.
With that being said, I will most definitely connect a 12v power supply to the compressor. I have a couple of thoughts as to how to accomplish this, but firstly, I need to ask; which of the connectors should the Positive go to and which for the Negative? I don't want to foul a good compressor by something as trivial as that. On to my thoughts as to the power supply. I can connect jumper cables from my Durango or my wife's van and connect the opposite ends to wires that I can attach to the compressor. Or, I have a battery charger made by Battery Tender, but I don't know if that provides a full 12v. I would need to connect the multi-meter to it and learn that info first. Which of those do you feel would be the best or is there a better way to accomplish this task as I would like to do as you said and learn from others before I learn the hard way needlessly. Thanks!


J

 

According to the Electrical Guide, Figure 05.3, the compressor receives 12V on the Red wire at the harness connector, the black wire is ground. The wires between the compressor's electrical connector and the compressor body itself may be different colors - just identify the terminal that connects to the Red harness wire and that is Positive.

The battery charger will be safer if it supplies a full 12V and sufficient current to operate the compressor motor. The only way to know is to try it. If it doesn't work, it may simply be that the charger can't supply the (probably significant) current the motor requires, so you'll have to try with your jumper cables. Just be careful not to short them or ground them. I've done my share of accidental welding that way! :-)

Alternately, you could connect your jumper cables to the Black wire on the starter motor, which is always at 12V even when the engine is shut off, and connect your ground clamp to the engine ground strap (lower right side of the engine). To access those you'd have to raise the front end of the car, but that would be worth the effort since it will make the compressor a lot more accessible for testing.

Don