How many pre-cat o2 sensors on a 01 bonneville ssei ?

[J.G]

Hello everyone ! does anyone knows how many ( pre-cat) o2 sensors does a 01 bonneville ssei supr. charge has ?? someone told me (2) but i only found (1). Im alittle confused Can someone help me !!

[KensSSEi]

i believe its 2

[00Beast]

There is 1. There are 2 total oxygen sensors, one before the cat one after. The front one is on the rear exhaust manifold, the rear one is on the exhaust pipe behind the cat. When replacing it, use AC Delco, Denso or NTK (NGK) only.

[willwren]

Ed is right, Ken is not.

The question was PRE-cat. ONE before. One after. The only one that can affect actual performance of the car is the single pre-cat sensor. The other one is only capable of watching your emissions and reporting a code (post-cat) with no affect on the vehicle or it's ability to run and perform.

[J.G]

thanks alot !!!

[KensSSEi]

my bad i always thought there was one right in front of the cat and one up near fire wall

[willwren]

The one by the firewall is BEFORE the cat. Translation: PRE-cat.
The other one is AFTER the cat.

But you were close!