Code P0420
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Legend
Joined: Jul 2007
Posts: 7,843
Likes: 13
From: DFW, Texas
Code P0420
So I know it means cat efficiency bank 1 blah blah, but here's what I did recently, help me figure out the best possible senerio to fix.
July07 - Factory muffler and cat removed, magnaflow muffler and hiflow cat added
3 weeks ago - Crank sensor modded, timing advanced, felt a little misfire, switched to 93 octane, no further issues.
2 weeks ago- Pulled both O2 sensors andsprayed them down with CRC Lectra Motiveelectric parts cleaner and reinstalled. No issues
Today - Cleaned engine bay with Gunk citrus scent. Careful as I could be with the pressure washer around the PCM, the PDC, battery, round air filter, etc. Drove home 5 min, no codes. Drove about 10miles, CEL lights up. Do the key thing, P0420. Drive to NAPA, guy sells me front O2 sensor, (wrong one according toobdcodes.com) Dark outside, so no fixing tonight.Truck still smells like I crashed thru an orange grove.
MaybeI sprayed an injector plug loose. I broke a couple of the red locking tabs fixing the plenum gasket inAugust, but that would be pretty noticeable, wouldn't it?
July07 - Factory muffler and cat removed, magnaflow muffler and hiflow cat added
3 weeks ago - Crank sensor modded, timing advanced, felt a little misfire, switched to 93 octane, no further issues.
2 weeks ago- Pulled both O2 sensors andsprayed them down with CRC Lectra Motiveelectric parts cleaner and reinstalled. No issues
Today - Cleaned engine bay with Gunk citrus scent. Careful as I could be with the pressure washer around the PCM, the PDC, battery, round air filter, etc. Drove home 5 min, no codes. Drove about 10miles, CEL lights up. Do the key thing, P0420. Drive to NAPA, guy sells me front O2 sensor, (wrong one according toobdcodes.com) Dark outside, so no fixing tonight.Truck still smells like I crashed thru an orange grove.
MaybeI sprayed an injector plug loose. I broke a couple of the red locking tabs fixing the plenum gasket inAugust, but that would be pretty noticeable, wouldn't it?
Record Breaker
Joined: Jul 2006
Posts: 2,440
Likes: 1
From: PA
RE: Code P0420
its the o2 sensor after the cat..replace it , reset the PCM And see if it comes back.. your on the right path with it..or just reset the PCM and see if the code comes back before you replace the o2...
Rookie
Joined: Jul 2007
Posts: 58
Likes: 0
From:
RE: Code P0420
i had the same problem a little while after i got a high flow cat.high flow and gutted cats dontwork well with the computer. get a o2 simm from the fastman and it willgo away and your truck will run better.
Thread Starter
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Legend
Joined: Jul 2007
Posts: 7,843
Likes: 13
From: DFW, Texas
RE: Code P0420
ORIGINAL: padodgeram
its the o2 sensor after the cat..replace it , reset the PCM And see if it comes back.. your on the right path with it..or just reset the PCM and see if the code comes back before you replace the o2...
its the o2 sensor after the cat..replace it , reset the PCM And see if it comes back.. your on the right path with it..or just reset the PCM and see if the code comes back before you replace the o2...
Captain
Joined: Nov 2007
Posts: 671
Likes: 0
From:
RE: Code P0420
To figure out whether it's the sensor or the cat, watch your datastream. Cat monitors should hover around 300 mV. If it is fluctuating like an upstream would, the cat isn't doing it's job. If it is stuck high, most likely a bad sensor.
Thread Starter
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Legend
Joined: Jul 2007
Posts: 7,843
Likes: 13
From: DFW, Texas
RE: Code P0420
FastmanO2 simm ordered,I'll replace the pre-cat O2 sensor tomorrow (original one; couldn't hurt anyway) andclear the code with my superchips and see if it returns. Glad I got inspected in Sept instead of later! Hopefully the simm will calm downthe jumpy idle I've had. Wasn't sure whatwas causing that, but after re-reading Dan's site, that hiflow cat just might be it.
I'll post back after installing thesimm for posterity purposes. (bookmarked)
I'll post back after installing thesimm for posterity purposes. (bookmarked)
