Lambda sensor stops working

[Wolf_Tm]

Hello,
I'm getting a strange problem in a friend's car:
after some minutes you are using the car, and more quickly if running it hard, lambda sensor stops working, lambda gauge on VT goes to max lean 1.83 and CEL switches on.
Everything returns fine again for few minutes if you switch off and on trhe engine.
Is there a way, looking at the logs, to understand what's going wrong in lambda sensor/v3 ecu controller?
I may add that this happens only after VEMS Support changed his ecu board, and never happened in 2500 kms with the old board.
Thanks