Originally Posted by jed960

That's not enough information to identify which sensor it is. B1 means bank 1, as it's an inline engine both sensors will be bank 1. The sensors will be either B1 S1, which is the first sensor before the cat or B1 S2 which is the second sensor after the cat.

Sensor heating doesn't usually have an effect on the emissions, not at the temperatures that the check is done anyway, I've seen VW group cars sail through the MOT emissions test with the engine light on and a sensor heating fault.

If it's the AQY engine, they are prone to ignition lead failure and a misfire could affect the emissions.