What is the other sensor in my Cat

[grsilvia]

I replaced the O2 sensor in my 90 C2 Cab and noticed a second sensor of some sort toward the back of the catalytic converter. I called two Porsche dealers to help identify the part. Niello thinks it is a cat temp sensor, but can't get that part because they think it was only used on the p-cars kept in country. Sportique (Russ) says he's not sure if he can get the part, but will call Porsche in Germany if necessary and let me know tomorrow.

My question is; Do I need this? I have a slight exhaust leak from where this sensor attaches to the cat so I would like to replace the sensor to fix said leak or if I don't need it I can remove it and replace with a screw in plug.

BTW: I have a diagram of the exhaust system that Russ faxed to me that I can scan if it would help, otherwise here's a pic of the p-car.

Thank you in advance, Gary

2nd O/2 sensor.

Provides better mixture control in closed loop mode.