Hello all, my recently acquired 2009 XF supercharged V8 has a very choppy ride. I have done some searching and here is a sample reflecting my experiences.

Already swapped the wheels to 18s, this car just never settles down.
There are no dash lights or fault codes. There is no indication as to what suspension mode the car is currently in. The power steering assist is very weak. It could be stuck in sport mode because if some sensor is dead which prevents voltage being sent to the shock, at which point they default to hard. Just brilliant engineering. Maybe in SDD, I have the cable on the way to check there.
The independent shops here have no chance to hunting this down, and to take it to the dealer I might as well replace the struts just to nuke this problem from orbit, they are probably due anyway.

The car has 155k km on the clock(-100k miles) and it seems like this is the time for everything on these cars to be replaced(again). The shocks are not leaking and have possibly been replaced by previous owner, he also did all the front bushings, I have done the rear.

The SC shocks are very expensive, as expected, because there is a magic solenoid in there that is not even driver controlled. Buy a whole set of non-SC shocks for the price of one SC shock. I imagine there will be a lot of people going this route as these cars crater in value, which doesn't surprise me anymore as to why after few months of ownership. Same as the people on the XJ forum using the S-Type SC shock to replace the air suspension. What are forums for..

I'm pretty sure the non-SC struts would fit, I will then have to figure out the sensor defeat. But even better would be the struts from the S-type, that car actually had very good reviews on ride comfort. The suspension on those is mostly identical to the XF, so I am wondering if anyone either knows they are the same or can point to measurement spec. Thanks!

XF SC struts
S-type struts

 

Watching with interest.

 

if suspension goes to hard mode 1) there should be reason for that 2) CATS system fault will be ligthen on IC if fault is electrical and probably if mechanical fault as well.


you will need disable adaptive dynamycs suspension module after changing struts as car will throw lights.


I thinking about upgrading my XF SC with softer springs but do not find ANY info on that (even colour marking in jags seems secret)

 

The IC is clear and OBD2 shows no codes.

Even taking it to the dealer who can troubleshoot these issues with a system capable of reading the proprietary Jaguar Chassis (C), Body (B) and Network (U) codes, the service manual states that the ADCM module only logs a code if the CATS error shows in the IC.

The CATS system is the ADCM, 2 accelerometers, and the solenoid in each shock. No doubt the dealer would just tell me to start replacing all the parts regardless if they find some code or not, and all 4 shocks first due to mileage. This exercise would total more than half the value of the car. The diagnostic fee being ~400USD is same as buying 4 new non-SC shocks and just unplugging the ADCM.

I will see if I can find something in SDD once I get that set up, before I pull the trigger on the S-Type struts.

 

in my case SDD show 3 of 4 solenoid faults, when actual fault was CATS ECU.

 

There's a thread on the jaginfo.org forum where a member replaced his XF shocks & springs with S-Type stuff in order to improve the ride, here. In that thread he was swapping non-CATS shocks, but since you have a 2009 XF with the older system the 2006-2008 S-Type CATS shocks should work on your car, I think. Either way it should be a softer ride. As always YMMV

 

Thanks for chiming in. For me it makes sense because if the CATS module dies how can it report a fault to the IC? I may try to get lucky at the bone yard finding the ADCM and sensors to see if it would make any difference because the high effort steering at low speed would remain an issue after swapping shocks. ADCM part number changes after 2009 so it would need to be year specific, retail is $400+ and $200+ for each sensor.

I am not sure if the steering column also defaults to sport mode? To say that this design is annoying would be an understatement. I imagine there are a lot of pissed off people cursing their Jaguar out there.

 

Thank you, I should have searched there but there are 4 major Jag forums(says a lot about the cars). If unplugging the ADCM doesn't show up red on the cluster, I would just go with the non-CATS shocks so problems with the system would not come up again.

 

CATS system is monitored trought other major system, and when something goes wrong it reports. In my case CATS ECU had corroded PCB tracks, and it reported shorted solenoids. I have measured all wired to CATS ECUand solenoids values, aven ascelerometers but nothing was wrong, once changed CATS error went out imediatly.


it surpsises that you do not get CATS fault, I always got yellow "CATS system fault"error. you cant unplug cats module - you get error on screeen every time. CCF need to be changed with SDD to disable this function, then it can be remooved.


I havent noticed any wheel steering weakness on sport mode. throtle comes more sensitive and suspension gets a bit stiffer thought.

 

Quick question - how does the adaptive dynamic system alter the ride stiffness (i.e. make the ride 'hard')? My understanding of the system is that it adjusts the damping, whilst the actual ride stiffness is determined by the springs' resistance to external forces. There therefore shouldn't be such a thing as 'hard mode' for the suspension to get stuck in....

 

there is soleniod. depending on its position one or two channel are available for shock flow.