C5 Audi engine control problem

[Radek]

Hello all;

2000 A6 2.7tt, 6-sp., the problem is still unresolved, persisting since last summer:
Car would not start unless the battery is disconnected for at least 30 sec.  It cranks but gets no fuel (no gas smell after extensive cranking).
Similarly, the engine controller would only respond to VAG-COM at the first query (once ignition is switched off, then back on, no response).  Codes are related to lambda sensors.

I was wondering about the ignition switch - could it be the cause?  I'd hope so, because a failed ECU means car is good for parts only, those ECUs are rare and expensive.  Is there perhaps a relay that controls power for the ECU? 
Thanks for any suggestions.

Radek.