Just bought a 2001 996 C4 US model. There's only one sensor / cat right at the input. why only one and what's the diff with the models who have 2 sensors / cat ?

Would it be easier (CEL) to install a cat bypass in those conditions ?

Thanks,

 

All 996's have two cats, and there is a oxygen sensor before and after each cat for a total of 4. Why do you think you only have one?

 

I know there is two cats but I see only one pre sensor on each one.

It doesn't seems to have a post sensor. Also I see in the engine bay only two connectors

 

Don't the European models only have a total of 2 sensors?

 

mine is a US model !!??

 

Here is a online link to the 996 manual.

http://www.cannell.co.uk/Manuals.htm