Cat sensor problem?

[FireFly90]

The fuse for my cat sensor keeps blowing and turning the engine management light on the dash, still runs fine but a bit baffled as to why it keeps blowing. Wondering if a wire is shorting somewhere or i need a new sensor? (hope not) =/

 

[PumaNoob]

Its possible the sensor is damaged, there is a heater inside them that the 2 white wires attach to. If there is a problem with the heater element it can make the fuse pop. Only issue is that they cost a bomb to replace. Would also be worth checking the power wire isnt shorting. IIRC its the grey wire on a 4 wire sensor. Black is signal, 2 white are heater.