XM sticks to hard mode

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bx19gt
Posts: 2
Joined: 28 Aug 2021, 05:45

XM sticks to hard mode

Post by bx19gt »

Hello.

I have already discussed this issue in the Club XM chat but thought I'd brainstorm it here also.

My year 2000 Xm V6 auto has developed a habit of freezing the rear suspension to hard mode. This happens when I park the car with suspension in normal height, as I usually do. The only way to get it to work again is to lower the car and raise it to normal height, which is quite a slow process with the 6+2 pump. If I park it in the intermediate height and after starting the engine lower it to normal position everything works fine, no need to lower it to the low-position. And it never sticks to hard mode while driving, only right after starting. I've had two error codes stored, first from body motion sensor and lately steering sensor. Both codes were erased and the suspension light now illuminates when power is turned on, as it should.

All 7 suspension spheres were replaced last year and the accumulator sphere in 2022. This problem became noticeable after the new spheres were put in, but the previous ones were Comforts so I can not say how bad the sticking was then, if at all. Electrovalves were equipped with diodes last year. Dirt in the steering wheel sensor has been suggested a culprit, but if this was the case then why would lowering the car release the rear suspension to normal operation until next start? Height corrector linkage has been greased and should work fine. The car has covered just over 62000 miles and is otherwise in very good condition.

So, is the electrovalve itself to blame? I have one NOS valve which I could swap to the rear, but before sacrificing it I would love to hear some other plausible theories.
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xantia_v6
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Re: XM sticks to hard mode

Post by xantia_v6 »

As I mentioned on club-xm.co.uk, the test of an electrovalve is whether there is any leakage into the return hose. There should be no flow of LHM into the return hose when in firm mode or soft mode, but there will be a spurt of LHM as it switches from firm to soft. Any continuous flow in the electrovalve return will cause the hydractive valve to stick in firm mode.

A leaky electrovalve can usually be repaired by stretching the internal spring: viewtopic.php?t=32782
bx19gt
Posts: 2
Joined: 28 Aug 2021, 05:45

Re: XM sticks to hard mode

Post by bx19gt »

Just today I got a new tip: the anti-sink sphere. It was changed last year and from what I've now heard it does not bleed that well automatically. So that might fit the symptoms and solution. Plus I've got a stored error code, again, guessing it is the steering wheel sensor once more so that will be cleaned just in case.