My 97 Z3 has a 420 code and not really sure what to do. I just got the car about 6 months ago. It has been sitting for awhile due to the owners health issues. I have changed both O2 sensors, replaced the injector “spider” vacuum hoses, plugs, wires, injector cleaner, not sure what to do next. The car has about 90 k miles and has been driven very little in the last 14 years. Any ideas?
A P0420 translates to catalytic converter efficiency below threshold. To simplify that means that the cat is not filtering as it should. Most likely means it needs replaced.
Not to diagnose by anecdote, but I had this code on an M52 engine and it turned out to be a lean condition due to a vacuum leak; in my case a hole in the lower CCV line.
US-129
Yeah, don’t jump to conclusions. It could be expensive and you find it’s not fixed. Is that a BMW code or a OBDII code? Lots of good info chasing emissions issues on E46Fanatics. You may want to do a smoke test.
George Roffe
98 M Roadster
01 325iT
I appreciate the feedback. This forum is very informative. I have heard a lot about this smoke test not exactly how to do it. I understand how to build a smoke generator just not how to use it.
I'm glad we have this forum, so I'm not sitting here wondering if Code 420 isn't some pot-smoker joke I'm too old to recognize.
Bookmarks