help! random P0420 with P0446
08-16-2017, 10:24 PM
#1
help! random P0420 with P0446
wow, it's been forever since i made a thread here! anyway, i've read about as much as i could & am still stumped...
i got a CEL for P0446 and P0420 a few weeks ago & can't figure out for the life of me why. a little background on the truck: 99 sierra with '01 5.3 swapped in. Blackbear tune for 8yrs. catless headers for 6.5 years (with rear O2s not tripping CEL). last retune was a couple years & 25k miles ago.
lately, i've been living off a dirt road, so the P0446 ain't surprising... last week, i crawled under the bed & pulled off the EVAP purge filter & blew out the line / cleaned the filter box (apparently it got the new removable filter at some point forever ago, so that wasn't hard). i'll have to get it rescanned to see if the 446 went away (my OBD tool's in storage
), but the CEL's still on.
the 420's really stumping me, though. i've checked for vacuum leaks, but everything looks okay. my gas mileage is the same as it's been for a while, so i don't think it's running rich, however i do smell the exhaust a little more. the last work that's been done was a new muffler & side-exit a couple months before the CEL.
any ideas?
i got a CEL for P0446 and P0420 a few weeks ago & can't figure out for the life of me why. a little background on the truck: 99 sierra with '01 5.3 swapped in. Blackbear tune for 8yrs. catless headers for 6.5 years (with rear O2s not tripping CEL). last retune was a couple years & 25k miles ago.
lately, i've been living off a dirt road, so the P0446 ain't surprising... last week, i crawled under the bed & pulled off the EVAP purge filter & blew out the line / cleaned the filter box (apparently it got the new removable filter at some point forever ago, so that wasn't hard). i'll have to get it rescanned to see if the 446 went away (my OBD tool's in storage
), but the CEL's still on.the 420's really stumping me, though. i've checked for vacuum leaks, but everything looks okay. my gas mileage is the same as it's been for a while, so i don't think it's running rich, however i do smell the exhaust a little more. the last work that's been done was a new muffler & side-exit a couple months before the CEL.
any ideas?
08-16-2017, 11:31 PM
#3
that's what's making me ask if anything else could be the culprit or if it's somehow related to the P0446. from what i understand, it basically just means that the rear Bank 1 O2 sensor is reading about the same variances as the front one... but you're right, it shouldn't come on at all, and it hasn't before in all these years.
08-19-2017, 04:31 PM
#5
hmm... maybe, but i just don't remember seeing the P0420 before with my own scanner (it's in storage right now). and if that's the case, wouldn't i also see the code for Bank 2 (P0430, i think)?
obviously none of the parts stores will clear the CEL so i can see if cleaning the filter worked or if i need to chase down something else. i tried unplugging the negative for a bit, but the only thing that reset was my radio preset list. does unplugging both cables & shorting them to the frame really work?
obviously none of the parts stores will clear the CEL so i can see if cleaning the filter worked or if i need to chase down something else. i tried unplugging the negative for a bit, but the only thing that reset was my radio preset list. does unplugging both cables & shorting them to the frame really work?
08-19-2017, 10:40 PM
#6
hmm... maybe, but i just don't remember seeing the P0420 before with my own scanner (it's in storage right now). and if that's the case, wouldn't i also see the code for Bank 2 (P0430, i think)?
obviously none of the parts stores will clear the CEL so i can see if cleaning the filter worked or if i need to chase down something else. i tried unplugging the negative for a bit, but the only thing that reset was my radio preset list. does unplugging both cables & shorting them to the frame really work?
obviously none of the parts stores will clear the CEL so i can see if cleaning the filter worked or if i need to chase down something else. i tried unplugging the negative for a bit, but the only thing that reset was my radio preset list. does unplugging both cables & shorting them to the frame really work?
Don't short the cables to the frame. That's not the proper way to discharge an electrical system. If there is still voltage, you could send a spike through the electrical system and wipe something out. The proper way to discharge would be to step on the brakes and hold for a few seconds. Any voltage would go through the bulbs.
Trending Topics
08-20-2017, 06:47 PM
#9
yeah, i'm sure Justin probably locks his tunes. thanks, though.
the trick with the brakes did clear my MIL this time... at least for now. i appreciate the help. i'll see if anything comes back when i start driving around tomorrow.
the trick with the brakes did clear my MIL this time... at least for now. i appreciate the help. i'll see if anything comes back when i start driving around tomorrow.
The following users liked this post:
Jonblarc7 (06-13-2019)