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Need helps with codes P0420 and P0430

32K views 8 replies 5 participants last post by  TheSatinPumpkin 
#1 ·
P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

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So I guess both rear O2's are bad but its weird both go off at the same time. I have cleared the codes and even reset the PCM but they come back.

I have no cats and the CEL for the rear O2's is disabled through custom tuning.

http://dodgeram.info/tsb/2007/18-016-07.htm

Any ideas?
 
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#2 ·
Try putting in new front sensors and see what happens? Or just buy one and add it in, see if it goes away.
 
#3 ·
Yeah i thought about that but wasnt looking to swap out parts to see what I get and that might not resolve it. But then again, with the truck being an 04 and 73k on it, it might be time to replace all of the O2's anyway.
 
#5 ·
THX man, as soon as I get back to my office I will read over it.
 
#7 ·
I had those CELs disabled through custom tuning.

But are those the codes guys get when they have no non-foulers and are not custom tuned?
 
#8 ·
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