Which lambda sensor is this?

[Slimy]

I've just checked my current fault code, and got;

17526 - Oxygen (Lambda) Sensor Heating: B1 S2: Open Circuit P1118 - 35-00 - -

Any guesses which lambda sensor this is on about? Is it the one before the cat or after?

 

[m0rk]

Post Cat

 

[Slimy]

Excellent, thanks!