P0420 Chrysler -

Question

02 sensor # 2 bank one reads .940 and does not switch after bank one cat replaced

Answer 1

Hi there,

This actually indicates the sensor itself is the issue. It should show a slow rolling voltage change, staying up close to one volt would mean there is no change in the exhaust. The front O2 sensor could cause this as well. If it's not changing the fuel mixture it might lead to this. I would watch the voltage on the front O2 sensor and make sure it's changing quickly.