Fault Code OBD II 0155 (O2 Sensor)

[Sir WIll]

Ladies and Gents,

The only fault code I am getting from the A8 is in regard to the 02 sensors.

OBD II P0155 Oxygen Sensor Heater Circuit Malfunction (Bank 2, Sensor 1)

Now this tends to come and go, I have days without the engine warning light on the dash. Then it pops back for a while to say hello then goes again.

Car drives fine, no problems and whether its on or not makes no difference to the driving of the car. That's all well and good but I would like to have it cleared so it stops annoying me!

Are we looking at here a case of a Lambda sensor swap, wiring or perhaps an exhaust leak (Though cannot hear anything)?