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Catalytic converter problem? (P420 code)
I'm trying to figure out my P420 code. I'm trying to see if it's my converter before I drop all that money on a new one. From reading everyone's posts, I've learned that the readings off the wires should be variable on the pre-cat and stable on the post-cat. Which wires do you probe for that? In the Chiltons, it shows that black is the ground and the pink is the pre-heat wire from the EGR. So I've tried the other two (purple and tan) to each other and both to ground. I'm showing a steady increase in voltage on both of those wires as it heats up but no fluctuation like described. I stopped there and didn't even go to the post-cat yet.
History on car...140,000 miles and just put a new 50k motor in about 10k miles ago. The original motor blew an upper intake which over heated the motor and toasted cylinders #1 & #3. I nursed it along for a while but the converter certainly was exposed to some serious oil and collant burning for quite a while. So the fact that I'm getting a suspect converter problem isn't that far out of reach.
Thanks for any help.
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