My O2 sensor heater circuit has gone bad on the rear Sensor.

So what i would like to know is if anyone knows what O2 sensors Mountune use for the rear one?

i need to replace this ASAP as not only is the weather dry this week, it is consuming more fuel and having an engine light on bugs me.

it could be a bad one thats failed early or could be the sensor isnt renewed by mountune and is a coincidence.

i have checked for faults in the wiring (Broken wires, chafed wires or exposed) No faults found

Mountune have an email and i am awaiting a reply.

thank you