XJ8 3.2 Sport '51' Plate with CATS - Intermittent failure?

[fast cars]

My 3.2 is fitted with CATS and periodically shows suspension fail on the dashboard and will go out as well by itself occasionally, used scanner but does not reveal any fault codes, can anyone tell me what i should be looking for to cure?

Thanks

[fatboy b]

Loose or damaged wire on top of the shocks?? I have AD on my XF, and the wires do look vulnerable.

[S6 Devil]

I've had this issue. I had the shocks off and the wires re soldered, but that didn't solve the issue. What did solve it was changing one of the accelerometers.

On my XJR there is one in the boot behind the petrol tank, under the carpeted cover. I bought one from a breakers, as they are expensive new. So far, so good. There is another located on the engine bay bulkhead. If the boot one hadn't sorted the problem, I would have changed the engine bay one.

[fast cars]

Thank you will check both out here, is it possible to remove cats, I don't like the ride compared to my sovereign but would I have a faliure on the dash permanently?

[S6 Devil]

fast cars said:

Thank you will check both out here, is it possible to remove cats, I don't like the ride compared to my sovereign but would I have a faliure on the dash permanently?

I tried this but had the suspension warning on all the time. The ride is quite hard, that's for sure!

[fast cars]

I unplugged and refitted all the fuses in the boot and ns heel board and its not appeared all day today??

[fast cars]

i

[fast cars]

And its back

[Dodsy]

very common on older XJ's for the compressor to get tired. When the air is cold it struggles to get the reservoir up to pressure. It throws an 'air suspension fault' and an orange warning light.

Get to an independent and get the codes read, that will confirm it then its around £350 for a new one plus <1 hour to fit.

Temp fix, turn it on for 2 mins (dont drive it), then turn off. then turn on and drive normally. It gives the compressor a bit more time to get things up to pressure. IIRC if it doesnt get up to pressure after 3 mins OR if you go over a certain speed (cant recall ,maybe 30 ?) and the tank isnt up to pressure then the fault comes up. The 3 minute timer resets when you switch off an on.

[fast cars]

Cool, thanks allot for that info, I didn't know they had a compressor for shockabsorbers! Its been behaving for the last couple of weeks so lets see...

[Dodsy]

fast cars said:

Cool, thanks allot for that info, I didn't know they had a compressor for shockabsorbers! Its been behaving for the last couple of weeks so lets see...

CATS is the Jag air suspension system. You can confirm its CATS with a quick look under the bonnet you will see 2 wires going into the top of each damper

It has a compressed air reservoir that is pumped up when you start the car then I think topped up as necessary. The air suspension automatically adjusts ride height and I believe stiffness (to limit body roll) as you drive so it needs a tank of air. If the tank doesnt get up to pressure in the time you get the fault. This is mostly caused by a tired compressor but can also be due to air leaks.

[Jaguar steve]

Dodsy said:

fast cars said:

Cool, thanks allot for that info, I didn't know they had a compressor for shockabsorbers! Its been behaving for the last couple of weeks so lets see...

CATS is the Jag air suspension system. You can confirm its CATS with a quick look under the bonnet you will see 2 wires going into the top of each damper

It has a compressed air reservoir that is pumped up when you start the car then I think topped up as necessary. The air suspension automatically adjusts ride height and I believe stiffness (to limit body roll) as you drive so it needs a tank of air. If the tank doesnt get up to pressure in the time you get the fault. This is mostly caused by a tired compressor but can also be due to air leaks.

No X308 XJ has ever been fitted with air suspension.

The OP's car is fitted with electricially controlled variable damping rate shock absorbers that are managed by accelerometers and the damping rate is adjusted depending on inputs from the accelerometers.

The X308 CATS system does not "pump up" or compensate for ride height or have a air reseviour or compressor. It's a conventional steel sprung and gas damped suspension.

You are presumably thinking about the air suspension system fitted to the later aluminium bodied cars which is a completely different design.

[Dodsy]

ahh I stand corrected, I was thinking about the X350 didnt cross my mine that it was an X308. Oops