CATALYTIC CONVERTER OPTIONS (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Maybe a different shop?
I'm not too worried about it, at this point I am accustomed to dealing with CA laws. I'm going to remove the cats and attempt to polish the shields and see if the laser etching becomes visible. Really I just wanted to spread the word on Magnaflow cats and CA requirements. For what you pay for Magnaflow cats you'd think they would stamp the Shields, but I am convinced the "weak" etching and rust prone material is by design to ultimately get more money from the end user.
 
I had the same code, but a very different "solution"
My charcoal canister was clogged, I took it out, shook it quite a bit and it was still solid. I was also getting quite a bit of pressure in the gas tank after every trip of more than a few minutes. The cap would push into my hand when removed and a hiss of pressure would release for several seconds.
When I replaced the canister with the one from a Pontiac (17092110) the code went away.
We'll see how it does in the California summer heat, but so far, after 4 months, i've had no pressure in my gas tank and no code.
 
I had the same code, but a very different "solution"
My charcoal canister was clogged, I took it out, shook it quite a bit and it was still solid. I was also getting quite a bit of pressure in the gas tank after every trip of more than a few minutes. The cap would push into my hand when removed and a hiss of pressure would release for several seconds.
When I replaced the canister with the one from a Pontiac (17092110) the code went away.
We'll see how it does in the California summer heat, but so far, after 4 months, i've had no pressure in my gas tank and no code.
Same P0420? Interesting that your charcoal canister's been triggering that. I have the same pressure and hissing sound everytime i open my gas cap although my cabin dont smell like gas just yet. Might consider replacing that as well. Just got home from a daytrip at Holcomb Valley. So far CEL didnt show up. Although on my way up my temp reached 213F and my AC stopped blowing cold air i thought i was losing coolant. It was around 8am and outside temps maybe in the high 70s. I checked my compressor and the lines connecting to the evaporator (afaik) was iced up so i turned it off. AC was working fine the whole trip (2pm outside temp maybe in the mid 80s) back down to OC though.

20250712_094309.jpg
 
P0420 usually points to dirty cats from running improper AFRs over some time. Unless the cats are blown out and you can see daylight through them, the precious round bits are probably coated with crud. Folks on YT have vids on how to clean your cats, if they'll sit in a tall turkey cooking pan over a fire. Most folks just swap them out but might be worth the option!
 
P0420 usually points to dirty cats from running improper AFRs over some time. Unless the cats are blown out and you can see daylight through them, the precious round bits are probably coated with crud. Folks on YT have vids on how to clean your cats, if they'll sit in a tall turkey cooking pan over a fire. Most folks just swap them out but might be worth the option!
I just replaced my upstream O2 sensor laat weekend so both of my o2s are basically new so lets see if CEL comes back.
 
I just replaced my upstream O2 sensor laat weekend so both of my o2s are basically new so lets see if CEL comes back.
The upstream O2 sensor has nothing to do with the P420 fault, only the downstream O2 sensor. These sensors don't go bad frequently but hopefully you're GTG. Still, don't hold your breath!
 

Users who are viewing this thread

Back
Top Bottom