2005 Ford Expedition Q&A

2005 Ford Expedition Question: CODE P0420

HAVE CODE PO420 WITH CHECK ENGINE LIGHT REPLACED RIGHT BANK CAT AND HEATED OXYGEN SENSOR BEFORE CAT. WHAT ELSE COULD BE WRONG? -
Answer 1
Did you change the O2 sensor before or after the Cat on your 2005 Ford Expedition? I know of one case (It was a Cadillac) where the rear O2 sensor, the one after the Cat failed in such a way to case a P0420 to set. -
Answer 2
We have same model, same problem. Ever figure it out? -
Related Items:
pulling a PO420 Code and cats have been changed and o2 sensors have been changed, still pulling Code
had check engine light code saying i had a bad catalytic converter on the left side, had it replaced, 2 days later the light came back on with the same code, took it back in, and was told now the r...