2006 S40 ECU damage by a short on the oxygen sensor line?

[adamk0]

Hello,
My 2006 S40 T5 ECU reported a missing rear oxygen sensor signal. It came out that one of the mechanics previously working on the car did not mount the exhaust manifold heat shield, so the wires going to the rear O2 sensor melted completely causing a massive electrical short between the heating and signal lines.

I put the new sensor in, and replaced the wires, but the CPU does not seem to read the sensor's voltage correctly. No matter what the engine rpm is, the ECU shows in Vida a constant 0.45V on the rear sensor... The actual sensor measured at the harness shows between 0.75 and 1V depending on the engine rpm, so what the ECU shows does not make too much sense. What is more, even if I disconnect the rear sensor, ECU still reports 0.45V on it.

Does that mean that the electrical short on the O2 sensor line killed the ECU? Is there any fuse specifically for the rear O2 sensor that could have gone bad and saved the ECU? What to do if the ECU is bad?

Thanks,
Adam