Can anyone tell me what the four sensors on the exhaust system are? There are two per pipe, one before and after the cats and there is a silver coloured lead going to each one. Only, the lead has come off one of the sensors towards the rear of the car on the nearside pipe and is dragging on the floor and I can't see a simple way of re-attaching it. Any idea of the effects of leaving this lead unattached?

the one before the cat is the O2 sensor, and after is the cat temperature sensor i believe

I'd have said O2 sensor before AND after the cat - to measure that the cats working properly.

 

Thats what my saab has anyway. Does ConZult show 4x O2 sensors???

NOPE!!! O2 sensors are before the cats. The sensors after the cats are the cat temperature sensor. If the cat overheats a warning lamp will light in the dash. The O2 sensors are used by the ECU to fine tune the air fuel ratio under cruise conditions...

 

Don't worry about that lead though - who cares if the cat overheats anyway... LOL

 

HTH

 

CheerZ,

 

Andy