Hi Everybody,

I went to the mechanic recently and the P0430 has been popping up more. I already changed the 4 Oxygen Sensor, the spark plug, checked the coil and after clearing the CEL, the code would pop up after 200 miles. Is this an indication to change the catalytic converter? I'm in San Jose California by the way and the Toyota in my area has a good online price where I can purchase and pick up. Any help would be grateful. Thanks.

Check my recent thread on this subject. For me it was exhaust gaskets. Cheers

Did you use Denso sensors? If there are no exhaust leaks (gaskets replaced), all 4 sensors, no vacuum leaks then it might just be the cat. Only the cats on the headers are monitored.

I had the same code pop up for me, I had to replace the catalytic converter. I also recommend going with OEM cats, aftermarket ones have a tendency to crack.

I had the same issue and ended up replacing the drivers side CAT PO430. I was told their was only one California Approved CAT available at the time for the 4Runner. New CAT and labor was $1000.
You should check the gaskets after the CAT to see if they are bad just to confirm its not the gasket.

Yeah I checked it and unfortunately it seems the catalytic has died. The Steven Creek Toyota Parts people said we can order the CAT on their website and go pick it up. The price was like $493.10 so I'll probably be doing that since I intend to drive that vehicle for a long time.

Scotty Kilmer (TV mechanic with 50 years experience) says if it runs right with all the sensors flashing - just ignore them and keep on truckin. BUT. I'd check the oil level.

2005 V6 4runner with 150,000 miles and I haven't had 1 idiot light come on since I owned it (15 years).

No rust anywhere on body - but superficial rust underneith. OMG!
SUV starts on first crank all the time. Rides great. Fast for a V6!
Change the oil and filter myself every 4000 miles - right in my driveway (gated communiity in Nassau Bahamas). Dino only. 4 Starters in 15 years. 4runner goes through them like free pizzas!

Had dealer change the transmission fluid (5 quarts) at 100,000 miles (holds 12 quarts)..

4runner is in Nassau Bahamas where it's 90 degrees to 60 degrees all year long. No body rust and I am 2 blocks from the ocean.

I could buy a brand new one, but why would I do something so stupid? Brakes were done once. 4 tires once.

Cheap potential P0420 P0430 Catalyic Converter Efficiency Fix

Or just throw a cat at it.

Do cats really go bad without something being majorly wrong with the engine?

I believe exhaust leaks are the main reasons for the codes, not the cats themselves


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Changed the converter today, prices weren't bad which I bought at Steven's Creek Toyota and they had the parts ready. Took the whole day job and I was going to film it for youtube but camera died. I'll post later on when the vehicle reaches 200 miles and see what happens.

They can crack from years of heat cycling.

Okay, 1,500 miles later, looks like the P0430 code isn't popping up yet. I checked both gasket on the front and the end of the manifold/catalyatic converter so looks like this issue has been resolved. Hopefully the vehicle will continue up to 300,000 miles.

mine only comes up on highway trips, p0430 and p0420, how easy was the exhaust manifold gasket change?.
any gotcha??

Yes, over time they become less efficient. The ECU can compare the readings between the upstream and downstream O2 sensors and tell when the cats are no longer doing their job, (removing pollutants). When that happens it will turn on the check engine light.

Which end though? The one at the engine block or the other side?

the ones you need to disassemble to tackle the p0430 and p0420 CAT error codes