Friend’s dad has a 99 es300 coach edition with 357.8k miles. Drives fine but check engine light is on and has P0420 and P0446. We live in California so I told him it’s fine for now but it will need to be fixed to pass smog. I told them to change the gas cap to see if the 446 goes away so he’s gonna look into that, but I’m wondering if they could be related and all come down to a single issue, since they’re both emissions codes?
no definitely not. One is to do with your exhaust, and other with your fuel tank. They are not connected or interdependent in any way.
how much would it cost to replace 1 or both catalytic converters?
Bruh there’s something called ask your mechanic I know you have one. Look on rockauto, oreilly’s etc for parts pricing as well. Stop having an MP moment (inside joke, for those of y’all reading). But it depends on how it was made from the factory: whether or not it’s bolt on or if it needs to be cut and welded. Also might be an extra charge if your exhaust bolts are rusted on like they always are and they have to bust out the torch lmao. Also we need California spec cats which are more expensive than 50 state ones. But before you put on an expensive cat make sure that’s really the problem.
if running premium or a mix of premium and gas would also help with the po420
no
Well the gas cap may fix one code but not the po420. Oh sorry the catalytic converters are just worn. Realize most of those vehicles have two catalytic converters on them and being that old they're not going to work as efficient even though it probably runs okay. Odds are one or both cats would need replacing to make it pass
Hi Scotty, my friend is the one who posted about my es300. Thanks for responding, how much would it cost to replace 1 or both catalytic converters?
I was also wondering if running premium or a mix of premium and gas would also help with the po420 as well. I haven't noticed any fuel smell and lately have been getting similar gas mileage for at least 5 months
Have you tried thinner fix by scotty? I am still about to try it to my mazda cx9. Same code.
Have you done troubleshooting for the different possible causes for the code, other than the converter itself?
Have you tried thinner fix by scotty? I am still about to try it to my mazda cx9. Same code.
Using a can of Cataclean would be as effective. It's the Italian Tune Up and with steady high rpms for 150-200 miles that help the cat. You're basically trying to heat-clean those honey combs inside the cat, or that's the theory.
Really should pressure test the exhaust first
