Have searched the site, cannot find anything on this...Probably a question for Don B!

We all know that the front Air-Shocks on our X350's invariably fail first...Braking loads etc. Possibly as a consequence of this failure, the X351 has Coil-Over fronts and Air-Shock rears.
My question is, if we were to block off the front air lines (Tucson Dave has already solved this for us in his post #14 at Sticky or Best Thread for Air Supsension Diagnostics? - Jaguar Forums - Jaguar Enthusiasts Forum) and replace the fronts with Coil-Overs, would the rears still work without error messages?

I am aware that a CATS warning would be incurred, but I already know that simply fitting a resistor to the CATS connectors at the Front Shocks will remove that warning (see William's post: #38 at: CATS system fault Error plus yellow ligt - Page 2 - Jaguar Forums - Jaguar Enthusiasts Forum

What say you guys (or gals)?

 

I think the change isn't so much because the fronts failed frequently, I think it's more that they realized that leveling the car for load is 99% at the rear. Many many cars have been available through the years with air adjustment load leveling in the rear suspension, although most were not entirely air suspension, but still coil springs for the main load, air for "over" load.

Opinions on why aside, as for setting up the X350 that way, I'm pretty sure it can't be done. The module will still try to adjust the fronts, and throw errors when it fails to see the expected changes in levels. The CATS can be fooled, but the leveling can't.

 

You'll still have the level sensors connected to the control arms front and rear to contend with as well.

There are conversion kits for converting the system to coil over and should come with the necessary items to blank out the module, etc.

 

I am obviously fully prepared to ne wrong here, but surely, if the front sensors are reading the correct height, then no error message would result? Additionally, the blanked air pipes would also show correct air pressure at the pressure sensor/regulator under the spare wheel and at the ASM, so again, surely no error message?

 

Okay, again I do not know the answer to this, but why would the ASM need to adjust the fronts if they were at the correct height? As you say, 99% of levelling for load is conducted at the rear?

 

One of the adjustments is to match the struts to each other, not necessarily to an absolute height. There is also the fact that the system lowers the car at speed (although not at US highway-legal speed...) and of course it won't be able to.

The fact the the fronts are always "right" doesn't mean the controller likes them. The simple fact that they don't respond to anything the controller does will throw a code, probably a "level plausibility error," at which point the controller gives up and stops leveling. Even the rear. Yoou won't be able to eliminate that behavior.

 

As long as the sensors, are fooled, into believing that all is well.
Then it should work, or one would think so anyway.

 

Apologies but I do not have much to add to this post other than my experience with my '05 x350 XJ8 45,000 miles. Early last year it had problems with rodents eating the wires after being parked for a long while. I had to have it towed to the Dealer for about $1200 of wiring repair. I picked the car up and it ran great, no fault codes for a while. Then the CATS error showed and it locked into firm mode. I have been driving it daily since repair so the rodents aren't a problem anymore. I took it for inspection in January and was told that it would cost about $750 to fix the CATS error. I had thought a lot about the pros and cons of having the suspension locked into firm mode as it was. In the end, for me, durability won out. I believe the air suspension is prone to failure and would last longer if the suspension was not always adjusting ride height and pressure. I kind of like the sportier firm feel, so I left the CATS error to ride. When it does fail altogether I will change to coil-overs. The car is sixteen years old and, from what I have read, the suspension is about due to die. I do not want to dump money in now only to have to dump much more in sooner or later.

 

Hi i think I will do the same and just drive till it's time install coil-over . Mine's from 2003 with over 200000 miles and still working .
LITTLE TIP
HANG A LITTLE STINKY BALL FOR the TOILET some where in the engine bay .... they hate the smell

 

If your CATS is not working and you intend to live with it, all you need to get rid of the CATS System Fault is four of these:

 

EsRay, that is very interesting seeing as how resistors would have to be added with coil-over shocks when the time comes. It would make sense to just add them now if it will make the error message go away. I should look into it. The rating of the resistors and where best to neatly solder them in seems to be the trick. Then coil-over installation may be a bit more inexpensive when the time comes, plus, no more cat warning to clear at start. Thank you for the idea. Can you suggest a spot where I can view a how to? If not, that is more than OK because when I get to it, I will post.

 

I simply pushed each end of the resistors into the female fittings on the end of each of the electrical connectors at the four Air Shocks and then secured them with a large heat-shrink.

20pcs Metal Film Resistor 1W 1% 1K ohm 1Kohm 1KΩ | eBay

 

That's a great idea, love those EZ fixes.
Like using the paper clip to bypass the hood is open sensor