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.
check engine light is on , my code reader says P0420. on 2001 Toyota Tacoma
by kwbtacoma in Cherry Hill, NJ on November 13, 2012
ANSWER by globalhelper on November 13, 2012
yes an air leak could cause this issue reseal 1st and see what happens
ANSWER by your.mechanic on November 13, 2012
yes it could