Thanks Don. I feel that it's pertinent to add that the CSF is intermittent and random at best. It always comes on at least once during a drive and rarely stays on the entire drive. It goes out and then comes back on at any given moment. It's gone on and off while on the same road, at the same speed, with the same flat terrain, and same smooth road. On and off during acceleration and the same with braking. As I'm usually concerned with watching the road, I don't recall ever seeing it come on during a turn. I hear the air suspension exhaust itself from time to time and it doesn't seem to matter if the CSF is on or not when it does. I usually hear it while braking. If I hadn't mentioned that in the past, I thought I'd try to sum it up here.

 

PWM is a means of regulating the amount of power. If the CATS solenoid is just an on/off system why wouldn't have Jaguar just used a plain 5V on/off? Is it a control valve rather then an open/close one?

Jason, do you know if the control module was replaced at one point?

It might not be easy but would it be possible to cross connect the wires to the dampers? That way you could see if the DTC fault switches over to the other damper or not and see if it's damper or electronics.

Guus

 

Hidy Guus,
I do not know if it's been replaced or not. The only things that appear to have been changed are the dampers themselves. I'm considering a salvage (breakers) yard for a set of connectors that I can add more wire to, to reach across the engine bay, so I can do the check that you're referring to unless I can come up with anther way with the materials I already have on hand. It's a very good idea. About the only way I can think to get the correct connection to the L side with the right side wires is to clip the connector off and then solder it back on after if I cannot find at least one for cheap and close. Any other ideas?

 

I wouldn't want to cut the connectors so if you can find a set from a salvage yard that would be best. It's a strange connector. Then you probably could use the paper clips to connect the wire to the original connectors with electrical tape.

An alternative would be to switch the complete shocks but that's easier said then done.

Maybe a strange solution but what if you left it till the intermittent fault becomes a permanent one? That might pinpoint the problem a lot better. Apart from the message appearing are there other drawbacks driving the car like this for a while?

My car has a slow leaking right suspension but I know it and let the compressor lift the car before driving off. I know the solution would be to replace the unit but since I'd prefer fitting two new units (€750/each without fitting ) at once I'll wait till I can afford to do so.

Guus

 

Guus,
I am beating my head against my desk repeatedly and hoping something useful comes out. My shift ends at 7AM EST, just under two hours from now, and I am off till Thur night. I want to get home and get started on this ASAP and would like to have a couple idea of how to do it w/o doing any damage to any wiring. It comes and goes so often, I don't know if it will ever go solid. It stayed on for a longer period a couple times last week and I thought I might finally be able to find the issue then, but it went off and on again. I've been able to test with it on a few times and when it was off with no variations in the results. Yesterday, it was on while I was in my driveway and I unclipped it from the damper and poked around a bit and clipped it back down. Looked inside and the light was off. It went back on shortly thereafter and I was unable to duplicate that again so a bad clip is not likely (I was kind of hoping at this point).

The paperclips on the right side clip will allow me to get into the clip, but attaching them to the left side damper w/o touching the sides is where I'm drawing a blank. Several ideas, but none seem like they'll work. Maybe I make a "clip". If I can get something small enough that I can put in the vice and use the drill press to put a couple small holes in, I can connect the wires to them. I can insulate the outside of each with elec tape. Perhaps a couple small bolts that I have laying around the garage. I can clip the heads off and with the vice and press, I can be sure I can drill straight and I have some very small titanium bits that should work. Won't look pretty, but I'm not in that for the looks. I need to get the SDD fired up before I do this and clear the faults. Then drive it until the CSF comes on, check the codes and then do it again with the wires swapped.

I was able to speak to the previous owner and the mechanic he used and there was a suspension issue in the past that the Jag dealer could not find and the little shop found a bent pin somewhere in the system. I looked them all over VERY well when I had the various sections apart and did not see any that were suspect. Wish me luck!

 

If you're making your own connector would an isolating material like wood or plastic would be better and drill holes in that to fit wires? As long as you can make a good connection the way it looks is not important indeed.

Guus

 

That is a thought. I don't need to put the wires IN the holes of the bolts, just ensure that they're touching the metal and nothing else...

But, you just gave me another idea. I can wrap a some tape around a couple wires that have no exposed wire on the ends and slide those down over the pins. As the pins are pointed, as long as I don't wrap them too tight or use too much pressure, I should be able to get them over the pins successfully enough to test. The more ideas, the better!!!

 

Guus,

You earlier referred to this thread:

https://www.jaguarforums.com/forum/x...uestion-76476/

In that thread, Cambo351 posted the link below, which opens a pdf document that explains the advantages of using PWM to control a solenoid.

http://www.axiomatic.com/pulse-width-modulation.pdf


One stated advantage is to increase system efficiency and reduce the heat dissipated through the solenoid coil. The document explains how the duty cycle is selected based on the resistance and inductance of the specific solenoid coil in order to achieve a constant current with low ripple.

Another stated advantage of using PWM is that by applying Dither (a small ripple) to the control signal, the solenoid can be kept in a state of constant vibration to overcome stiction (static friction) and hysterisis (lags in solenoid response relative to system inputs) so the solenoid will operate more reliably and predictably. My understanding is that this becomes very important in solenoids that are expected to open and close quickly and frequently (as in hundreds or thousands of times per second), or which must be expected to open or close instantly without delay. If you look at the scope shot Cambo351 posted, you can see small ripples at the tops and bottoms of the rectangular waves. I believe those ripples must be the Dither in the signal that controls the CATS solenoids.

It is interesting that the example used in the pdf is a "hydraulic valve," since my assumption is that the CATS solenoids must be hydraulic valves.

The copy below is taken from http://en.wikipedia.org/wiki/Active_suspension :

Solenoid/valve actuated

"This type is the most economic and basic type of semi-active suspensions. They consist of a solenoid valve which alters the flow of the hydraulic medium inside the shock absorber, therefore changing the damping characteristics of the suspension setup. The solenoids are wired to the controlling computer, which sends them commands depending on the control algorithm (usually the so-called "Sky-Hook" technique). This type of system used in Cadillac's Computer Command Ride (CCR) suspension system."

Cheers,

Don

 

Don,

I read it again but to be honest it doesn't make much sense to me to use it on a on/off valve.

First, I think the CATS system isn't switching that often that heat would really be an issue.

Second, there's a downside to introducing high frequentie switching into a system. If we change an on/off motor controller to a VFD or drive into a factory we always have to update the cables to avoid interference with other systems. HF has a bad habit of creating a lot of EMC.

On a control valve it would make sense to use it for precise positioning.

But I don't know what the Jaguar guys thought up! ;-)

Guus

 

Hi Guus,

I edited my message to include some more information that I think offers a more complete explanation/understanding...


I don't think Jaguar engineers thought up any of the air suspension system. I think all of that technology was developed by others, primarily WABCO, which manufactures the entire system except for the shocks (WABCO does manufacture air springs and air shocks for trucks, buses and other commercial vehicles).

WABCO's air suspension control technology is called ECAS, which is suspiciously close to ECATS (Jaguar's term for the system on the X350). According to WABCO's documentation, ECAS is easily adapted for the specific characteristics of any vehicle, from passenger cars to large earth-moving equipment. I think it's safe to conclude that ECATS is simply WABCO's ECAS adapted for Jaguar passenger cars.

Cheers,

Don

 

Don,

Thanks for you clarification!

It could very well be that the solenoid is indeed a valve used to restrict the flow instead of an open/closed valve. Maybe the (original) system is even capable of more settings then just soft and firm.

Guus

 

so I got home from work and change the oil and the filter to mobil 1 full synthetic 5 w 30. I pulled 2 of the plugs to check their state. They both appeared to be in excellent condition. I ran back up to the parts store to return the windshield wiper sizeI need to start a new session to find out what this check engine light is about. Also, the windshield washer fluid hoses have what appeared to be proprietary connectors that will only connect to certain sizes of windshield wipers. The rain X and the Michelin single blade wipers I was looking at will not work. What are the correct wipers? I never ever thought that would be a difficult questions. Lol

 

Hi Jason,

Your best bet with the wipers is to find refills for the rubber only. On our '04 XJR, the Driver side is a narrow 23.5 inch (an N24 refill with 1/2 inch trimmed off) and the passenger side is a narrow 19 inch (N19). I had to order refills online since all the local auto parts stores have discontinued wiper refills and stock only complete blades.

Search this forum, because someone has posted some different options for replacing the wipers and I can't recall the details.

BTW, I found this YouTube video from Bilstein demonstrating some of the features of air suspensions like the one in the X350 (the air spring/damper units shown even look like the X350 units). Unfortunately the video is not particularly illuminating, and it doesn't show the variable damper firmness function, but it's kind of fun to watch and the music is "trippy," as one person said in the comments.



Cheers,

Don

 

thank you for giving me something to do while I waited the SDD software to load. Lol

 

Patience is a virtue Jason! ;-)

Guus

 

My only guess is that all the tests I did are showing up as past faults... Ideas?

 

Yes, it looks like it and I would expect so.

Guus

 

Jason,

If you are referring to the "broken" chain link symbols for each of the DTCs, I'm not completely certain that symbol indicates that the DTC is "past." According to the manual, the broken link symbol indicates the DTC is "Pending," and the explanation is:

Pending
Applied to a continuously monitored DTC that is explicitly reported as Pending (for example, a fault has been detected in either the current or previous drive cycle, but has not yet been present for the necessary complete drive cycle to enable it to be transferred to the logged state).

I recall reading that some DTCs will not be logged until the fault is recorded for at least 2 drive cycles (maybe even 3 cycles for some DTCs).

If you have cleared all the codes recently, but have not driven the car through 2 or 3 "drive cycles" since, maybe it would be a good idea to not clear the codes now, but instead to drive the car again and check afterward to see if any of the broken links have turned to solid links ("DTC Permanent") or broken links with the little "ray" lines emanating above and below ("DTC Intermittent). As it is, I'm not sure you can make any definitive conclusions from your scan results.

Based on my own limited experience with SDD, I suspect that a lot of these Pending DTCs are triggered by turning the key to Position II and then back off without starting the engine, or by turning the key a little too far and almost cranking the engine, but then backing off to Position II. I've had similar long lists of DTCs, but after clearing all the codes and rescanning, only a few codes remained. I hope most of your codes are erroneous also, but it will be interesting to see which of them remain after you've driven the car through another heat-up/cool-down cycle or two.

Don

 

Looking at the messages most DTC's look damper related so I think they were triggered by Jason's experiments with the suspension.

Don, you're right that sometimes DTC's are generated when you have a bad start of the car but in these look all related to me. If there "start" related you usually also have ones like low battery voltage or CAN-bus errors or errors in a modules. All kind of random messages really.

Since the SDD is based on logging DTC's over time it might be wiser to leave the DTC's and use the car till most have been cleared again. Pending DTC's do indeed usually clear themselves after a few cycles.

Jason, I think it would be wise to evaluate all the things you've tested so far and see what the next step should be.

I still would like to hear what other things you notice from the car apart from the light coming on and the CATS message appearing. Does the suspension get firm too?

Guus

 

Lol... So they say. So is a Smith & Wesson M&P15T with a 40 round mag and a Tac-Con auto-reset fire control system and extra mags on the hip! Heh (not to mention the M4 Ghost Gun I just completed!)