check engine light is on , my code reader says P0420.
2001 Toyota Tacoma Question: check engine light is on , my code reader says P0420.
i found that the nuts that hold the downstream 02 sensor on the pipe rusted completely off. could air leaking in cause P0420? i put hose clamps around it to hold it on. the light is still on after a few trips. putting new nuts and gaskets on eventually. - kwbtacoma