Self levelling issue….(!)

[svvg]

Hi - I’ve got a strange issue which I think I know the answer to, but interested in others thoughts please.

I have a 2004 4.8 X5, with dual axle air springs. I rebuilt the pump with a “bagpiping andy” kit a few years ago, but recently have an issue with the dreaded “self levelling inactive” error message again (the code states accumulator fails to fill on demand…”.

I initially thought I had a weak battery, as I had this issue before, and it caused the same error - using the “hidden” menu on the dash my voltage seems to drop below 12v and keeps falling. I replaced the battery, but the same problem persists. I also hooked a charger up, and left it attached. Each time the code will clear with INPA or dis, but it comes back on as soon as the car moves.

Now the odd part…. The accumulator shows 12.2 bar each time the system fails. If I run the car and then clear the codes with the engine running, the accumulator will then fill to 15.5 bar (I think it goes to 15.5….), and it’ll all work for a few days again….

My thoughts on this are that the pump is worn again, and hence running, but is weak. With the engine running it gets the extra kick of voltage (up to 14 ish) to make it work that bit harder in order to fill the accumulator…????

I am not convinced by my own logic - but have ordered another rebuild kit, as they’re only £25, but if anyone else has any insights I’d be very grateful.

The car doesn’t sink or sit too low - so no obvious air leaks - and sensors and pivot arms on the sensors should be ok, or it wouldn’t work for the day or so in which all is well…

Many thanks for any suggestions.

And does anyone want a near new yuasa battery which I didn't need to buy…. Cost me £140! Bgger.