P2270 Chevrolet -

Question

Theres two sensors is it the first one or second

Answer 1

P2270 H02S signal stuck lean Sensor 2

This is sensor 2 which is the downstream 02 sensor , or the catalytic monitor sensor, any time you replace a 02 sensor on this year make and model you perform a heated oxygen sensor resistance relearn reset notice. By use of a scan tool that does factory protocal, If you do not have one available, just do a code clearing with any scan tool regardless if there is a code condition or not. this will reset the 02 resitance relearn value. What this does is reset the engine monitor and the ECM will learn the 02 resistance.