Last week I got my P0420 cel. So after reading up on it, I decided to take off my RP SuperCat and inspect it. Normally, its the cat's fault...

But look @ the pics...




Correct me if i am wrong, but isn't that cat in great shape?

Now, i decided to replace the gaskets on each end of the midpipe.


I reset the ECU and went through 4 drive cycles, and sure enough, P0420 again.

I then took out my O2 sensors....

(Left: Stock | Right: Bosch 4.9 for my AFR gauge)

Should I attempt to clean my stock O2 sensor? If I replace the O2 sensor and the code still comes up...what then?

Thx in advance for the help.

 

Don't 'clean' your sensor - the outside is just a steel shell, and if you do get to the guts, it won't work anymore.

It is very likely the cat. Your cat is in great mechanical shape, not plugged and honeycomb intact, but the coating can still be toast. High heat, metallic additives from lube oil, lead from leaded gas etc. will all kill the catalytic activity and leave just a ceramic sieve.

Part of the 80k mile emissions warranty, take it to the dealer when the code shows and let them do the math.


S

 

at the dealer we've had issues with different then stock sensors and the stock ecu setting off the p0420.

just speaking from personal experience, no saying it's common.

kevin.

 

damn, we'll i still have my stock cat so I can swap it out.

I guess i'll save up for the AP Dual Resonated Midpipe...

 

Sorry, I missed that it was an aftermarket - if you swap back and the code disappears, you'll know for sure.

My Random Cat only lasted six months - it is now my 'dual-resonated' midpipe!

S

 

no worries, thx again S