Wonky D2 ACE

So after a failed airspring replaced successfully and 150 miles without drama, I come out of the Mole Valley store to find the rear suspension fully extended. Load up with bale wrap, probably 250 kgs, nearside sits down slightly. Drive off and the osr jacks up to the point of rebound.

Get home undo rear air supply pipes from compressor to let rear sit on bump stops. Pull compressor fuse. Sits level. Run engine jacks herself up on drivers side with front and rear ACE. NO ACE lights on, if I pull the fuse whilst running puts up amber ACE but no relevelling. If I pull the fuse without engine not running refuses to start.

Where do I start with fault finding?

Initially thought sunroof accelerator as a bit of a leak, but then I have been getting a whirring which I thought was the air suspension when I turn off for the last 7 or so years (owned from new), never changed fluid and can't recall changing the quaze filter.

Any pointers appreciated!

You have to check the SLS ride height sensors to not have one snapped or bad contact in the plug and if they look OK the SLS needs recalibration with dedicated tester... IMO the ACE has nothing to do with that

Ok, but I disabled the sls by disconnecting the airlines and pulling the compressor fuse. It was level but when I restarted it she decided to jack up on right (drivers) side.

mabbs said:

Ok, but I disabled the sls by disconnecting the airlines and pulling the compressor fuse. It was level but when I restarted it she decided to jack up on right (drivers) side.

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that's normal as long as the vehicle was on bump stops level with the rear suspension totally deflated cos the ACE builds up pressure in the rams when it starts and the rams are on the right side but you wouldnt have noticed any difference if the vehicle was on normal height

Was sat firmly on bump stops with no air in sls system. Not sure if related but the rear sls sensors although attached rubber around trailing arm has split, so will replace. Will change ACE fluid and filter as only ever changed filter and that was 70k miles ago. Reading the web it mentions to crack off the return pipe to the reservoir and turn over engine without starting adding fresh fluid to the reservoir and to keep doing this until fresh fluid appears. Just wondering if also to crack off the unions to the rams to let old fluid out?

Not sure if a worn ACE pump would give these symptoms or it is a stuck solenoid in the valve block? Is there a way of doing a hard reset on the system without nanocom etc?

mabbs said:

Not sure if a worn ACE pump would give these symptoms or it is a stuck solenoid in the valve block? Is there a way of doing a hard reset on the system without nanocom etc?

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Read again what i said... the ACE has nothing to do with what you described cos it's normal to lift the RH side a bit if the vehicle is on bump stops so IMO it works as it should... though a fluid change is a good move anyway, no such thing as ''hard reset" on a D2

My error, although pulling the fuse on the sls which is also the abs etc the air compressor still kicks in, so something on the air side. Ordered level sensors and an airbag (as garage only changed the one which was faulty at the time). Pulled filter on ACE and washed in petrol was filthy, so full change and new filter required - good preventative maintenance.