I've been plagued with hard suspension for some time now on my X350 TDVI. I dont get any warnings and no fault codes are found. You mention the ASM gets its speed information from the instrument cluster. Is it possible this could go faulty and is it worth trying a replacement cluster...

Thanks Steve

 

Hi Steve,

I have moved your post to start your own thread to address your specific concerns. The default state of the dampers is Firm, so if yours are not entering Comfort mode, something is misbehaving in the ECATS adaptive damping system. Problems like this will typically flag Diagnostic Trouble Codes, but they will be proprietary Jaguar Body (B-prefix), Chassis (C-prefix) and/or Network (U-prefix) DTCs rather than the Powertrain (P-prefix) codes that can be read by generic OBDII/CANBUS scanners. Have you had it scanned by a system capable of reading these proprietary Jaguar DTCs? My advice is to not spend any money on parts until you have done so.

Cheers,

Don

 

I agree with Don, the IP is not likely to be the cause of your issue. The IP is the network gateway for the entire vehicle, so if that was not working you wouldn't have a functioning car. The ECATS system probably defaults to firm whenever a fault is stored due to any number of errors. Check with Jaguar SDD for codes before going further.

 

Can you be more specific: eg does it seem to be permanently hard, or only to switch to hard occasionally ? Under what conditions does it seem to change, and ditto change back (if it does) ?

+1 on getting your codes read through the OBD.

 

Get the codes read with SDD
If nothing there is relevant, remove the plugs from the top of the struts
Do a test drive and see if you have any difference

Removing the plug forces the strut into firm mode
If you have no change the struts are stuck in firm mode

Check the wiring between the ASM and struts
Assuming you dint have an accelometer failure code your up for an ASM

Cheers
34by151

 

Thanks for all you replies Gents. Ive been back and forth to an Indy who havent found any codes. They did some adjusting with height sensors. Still no success though.

The car rises when I start it and self levels when I stop at lights etc. It will also bounce up and down when i dab the brakes when slowing right down. But when I drive it I can feel every minor bump, the car feels stiff as a board.
When going over speed bumps it feels as though the back end has lifted of the ground.
I will try removing the plugs of the struts and take it for a drive as suggested.

Thanks again Steve

 

What wheelsize do you have ? Have you changed tyres recently too ? It is well known that large wheels/low profile tyres are not conducive to a comfortable ride. If you came to your car from one of the older XJs then don't think the ride is anywhere near comparable; it ain't ! For the big saloons, Jaguar really did lose the plot on ride quality compared to the old cars. I'm on my 2nd X350 and its the same as my first; namely much harsher than the XJ Series 3 I once had, and I'm on 17" wheels with 235/55 tyres too !!

 

Hi Steve,

From your description, Fraser's question about large wheels/low profile tires is a good one. Also, I wonder if you may have some failing rubber bushings in your suspension, which is a very common problem. The car bouncing up and down when you step on the brakes sounds like one or more of your shock absorbers may also be failing. You can do a basic test of the shock absorbers while the engine is running by carefully pressing down on each corner of the car and releasing and uwatching for no more than 1-1/2 rebounds. Just take care where and how you press on the car since the body is aluminum and the bumper covers are plastic. By the way, the aluminum body of the X350 is why it weighs several hundred pounds less than earlier Jaguar saloons, which is one of the reasons it doesn't glide down the road with the same imperturbable inertia as those earlier cars.

Cheers,

Don

 

First off, height sensors don't really have an effect on whether the dampers are in the hard or soft state.

Secondly, ... "It will also bounce up and down when I dab the brakes when slowing right down." ... I really don't think you'd notice that if the dampers really were in 'hard' mode.

It's worth knowing ... when the car is stationary, even with the engine running, the dampers are in hard mode; it's only when the car starts moving that they switch to soft; they actually switch over at 1 kph ie 0.6mph.

As you surmise the acid test for what state they are in when you're moving is beforehand to disconnect one (only needs to be one) of the connectors on the top of a suspension unit; the front ones are by far the easiest to get at. That will force the system into its default mode, which is 'hard'. Then drive the car and see how it feels.

Otherwise, check your tyre pressures; if you're running with the high speed/high load pressures then put them down to the normal pressures ie the lower pressure given on the inside of the fuel filler flap. When I got mine I found it quite hard ... until I found all the tyres were set up at around 38 to 40 psi. When I brought them down to the recommended 28/30 psi it made a big difference, it was far better.

Otherwise, as Fraser says, these cars are fitted with excessively low profile tyres, even from a performance point of view (pure straight line 'drag' acceleration excepted). It's purely visual fashion I'm afraid.

The irony (it seems to me) is that by having very low sidewalls combined with very wide treads we're pushing tyre flexibility back towards the inflexibility of the old fashioned cross-ply tyre.
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Wrong post!