1999 Merc E280, W210, non start

[Liteace]

Got here:
1999 Merc E280, W210
Engine 112.921

Bosch 0 261 206 300 engine ecu

Its a non start, engine management light on, cooling fan running constant, no coms with engine ECU,

Ive load checked +12 battery and also +12 ignition to engine ecu and as far as I can see from WD's is A2 (ign) B4 (bat)
A3, 7, 8 and F8, 15 are ECU grounds, also load checked them as well and all good

checked can on ECU D11, D12, thats there. anything Ive overlooked, anything common on these

Thanks

[mercis]

test communication with donor ecu