CPLJ

Thanks for the input gentlemen. As far as I can see the car is rodent free! We replaced the sensor and it still came up with the same problem which led us to think that the problem is within the wiring loom rather than the sensor. Is there any area where the sound system shares an area/conduit with the O2 sensor wiring?

Over the last few months I have been getting extremely loud and random static noises on the radio and disc but not on the voice from the satnav. This week the engine warning amber light came on and it was the oxygen sensor downstream of the catalytic converter. This was replaced but the light came on again after 20 mins. The sensor was initially outputting 450mV which then increased to 1V causing the light to come on. The garage reckon that there is a corruption of the O2 sensor potentially through chafed wiring somewhere in the loom and this was reinforced when I told them about the sound system. Is there a part of the wiring loom of a 2005 RX400h that is particularly prone to wearing/chafing so I can save the garage a bit of time?