Originally posted by DemonSVT:
I was just addressing the issue he was thinking every 420 code meant a bad bank 1 precat. It doesn't really have to mean anything is "bad" at all.
Sorry if I gave that impression, but I know that a bad O2 sensor can throw a P0420 incorrectly. But from reading most of the posts on this topic, it seems that many people have replaced the O2 sensor (including myself) only to have the P0420 come up again (thus implicating the pre-cat).
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
| 
