"air susp. Inactive"

I have read / searched a few of the previous threads on this message but still have a few questions , if anyone can help....
Vehicle is a 2004 TDV6
I get the " AIR SUSP INACTIVE" message on the dash board and no lights at all on the centre consul / height adjustment switches.
I have diagnostic tested it with the Autologic equipment, which says " cannot communicate with ECU"

So....
Is it an outright ECU failure ?
Where is the ECU ? ( under pax seat )?
Is it simply order new ECU and unplug/replace and retest with the Autologic equipment ?
can I purchase an ECU from anywhere but a main dealer ?
Anybody have any ideas of part number ?
Is it overhaulable / repairable ? ( the ECU)

I am trying to avoid the main dealer experience - not so much on cost but convenience. they want the vehicle for 2-3 days, are unable to provide a courtesy vehicle and I generally get the impression that they dont want to know.

Your expert help / advice appreciated

I didn't think they made a "TDV6" in 1994 ...but then again I could be wrong ...

sorry - duly edited to 2004

Eeeeee John ... Yer as bad as me Mate ....Th'old Altziemers is Kickin in there

Or as one of my Engineers used to say ..."Boss yer havin a CRAFT moment again"

Cant Rember A Fookin Thing

Personally John I don't know ..BUT...... Guys like Irish Rover & the team will/should be on the boards after tea .. They'll get yer sorted mate ..NO PROBS

When everything is working properly the L322 is a breeze to communicate with,in your case the comms are probably being held down by the K bus being shorted to earth - usually within the headlight levellng ecu or its plug.It is located in the LH A post behind the plastic trim,bout the size of a fag packet and from memory the top of it and the plug is a purple/pink colour.Unplug it and look for green gunge in the socket.
Other causes are usually water ingress related,often in the gulley under the step on either side sill in the front door shuts.
Once comms have been restored its good practice to reflash the eas ecu with the latest software as the original was not too good.Often the resevoir pressure static while filling is the fault logged.This is generally a tired compressor.
Sorry to use the words often,generally and usually - but without seeing the actual car its hard to be more specific.

the water ingress scenario in the sills is interesting as at the time there was recent heavy rain and on opening the drivers door, rain water was escaping - I thought - trapped inside of the rubber door seal at the bottom - are there electrical switches in the sills ? - how do I get at them ?

eightinavee- I am not that far from Bath .......

Have you got this sorted yet ? If not send me a phone number by PM and I'll call you.

spent the week end checking for water ingress pretty much anywhere - incl compressor but all like new
anybody know where the air susp ecu actually is ?