O2 Sensor Circuit Malfunction

[olivarrr]

The Clio (1.4 16V 2003) is running really rough when idle, seems like it's going to stall all the time. Engine light comes on intermittently, so plugged my OBD2 scanner in, and it says "O2 Sensor circuit malfunction, bank 1 sensor 2"

I'm going to guess its one of the O2 sensors which has gone? Does anyone know which one is sensor 2? Front or back? Or if it's another problem altogether? Cheers!

 

[Mr Trailer Man]

Sensor 2 is after the cat. They don't affect the running of the car though, just an emissions warning.

Sensor 1 controls the running of the car fueling wise.

Maybe your cat is on it's way out.