Ok Any help appreciated
Q. what would cause the back suspension to suddenly hit stops whilst driving with no warning? Air susp inactive up

Q2 what is that dull motor/hoover noise that is permanently on underneath mid body excluding suspension air pump?

This is second time its done it
last time local garage jacked up, reset code and it lasted 3 weeks.

no leaks stays up and operates normally

I am waiting on Gap tool!

could be a few different things really, but check all the height sensors are in good nick, one could be damaged or the linkage broken and cause an error which the ecu can't understand.

noise could be the fuel burning heater, or the inline fuel pump.  There is nothing that can't be fixed with a hammer😜😜
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Ta for that \ill search out a photo and have a look

mine has slightly different symptoms - came out one morning and it was on the stops all 4 corners, but set it to off road and it went up, then set to on road and all was OK but a few days later got suspension fault in dash. Wondered if it could be a leak in one of the springs so set it to off road height and went round listening for a leak - couldn't find one, and it stayed up all night so no leak. Then thought it could be a sensor, so bit the bullet and bought an IID tool.Arrived today, and sure enough h I have a fault code 'right rear height sensor voltage value out of range'. Now waiting for a replacement sensor from Dan, will let you know the results but I guess as the car spends most of its time in on road height there is a dead spot in the sensor due to wear. 2006 (56 Reg) 4.4 V8 Vogue In Bonatti Grey (Gorgeous!!)