i just had these exact codes and all four 02 sensors where changed by the previous owner. i made and 02 spacer with a tappered drill bit and some spark plug foulers found at autozone. cleared the codes and no return yet and its been a few days. my cats where bad for sure. was thinking off either getting the obx headers or a turbo kit from cxracing as the oem replacement is 1k from lexus

 

I think the PO430 leans more towards the cats being no good. I think PO125 leans towards something going on within the effectiveness of the o2 sensors. If you've had all 4 o2 sensors replaced and your still getting PO430, might wanna replace pre & post gaskets to the cats and maybe exhaust all around. Confirm there's no air leaks because that will affect o2 readings even if they're all new. It all works together. I'm about to take my car to back to the shop now to get that o2 replaced real quick. I hope everything goes well and that CEL stays off FOR GOOD.

 

in last few months i spend around $2000 on suspension
im gona change this car for a new (used probably but newer) in a year or two so im not gona spend another 2k for cats
problem is that im gona have to pass inspection this year

 

Try this to see if it cures the problem at least thru inspection. The cats on our cars are TOUGH. So I'd recommend just buying all pre and post gaskets to the cats off www.sewellparts.com... if your metal around your headers are deteriorating, I'd recommend getting 2 of each gasket to double seal it in any way to avoid ANY air leaks. And get all 4 Denso o2 sensors off eBay, Amazon, Rock Auto, etc. That's way less then 2 new cats, and it's a very good possibility it'll shut off the CEL IF your cats aren't completely destroyed internally.

2k on suspension, wow! What have you done to spend so much??? Please share with us bro! Hope all goes well!!

 

Why not take the car to a mechanic who has the tools to diagnose the problem instead of just throwing money at it as people seem to be suggesting? They can measure temps pre and post cats to tell if they're working properly. I have the same code right now, I know I've got a a leak that'll be fixed this spring, hopefully that'll take care of my code.

 

i will have to find mechanic that have equipment to check cats and o2 sensors because my mechanic is low tech
i changed upper lower and caster arms plus ball joints 4 struts strats mounts and probably some other stuff plus life time aligment ( had that infamous shake)

 

I don't know how common that equipment is but it seems like bad advice to start blindly replacing parts that may not be the problem unless you've exhausted all other options. I'd check with a good exhaust shop, they'd probably be able to check the cats.

 

The cats on these cars despite heavy mileage and seasonal conditions are very TOUGH. I recently replaced mine and all the surrounding components and after inspecting old cats, aside from rust, the insides were intact. Of course it deteriorates but they're fairly durable.. so I say all that to say this, just replace all gaskets on the exhaust system and all 4 o2 sensors and you will all notice more power and most likely less codes if not any at all. If your cats are still in working condition, those repairs should help tell and it will restore power response. Believe me. And it's less expensive then buying 2 new cats.

 

Even if it's cheaper than replacing the cats, why would you spend $300 replacing the o2 sensors and gaskets if you don't know whether or not they're bad?

 

I'm just tryna help out that's all bro. Seems like everyone wants to clear the codes without spending the $$$.. so my best bet is to seal up all air leaks and get new o2 sensors. Never hurts to know you got all new o2s and no air leaks. If that don't do the job, then the cats are probably going bad. There's nothing else to the exhaust. Replacing one and leaving the other 3 old might do the job. But it won't read evenly on the machine and Eventually the code will return. These cars are sensitive when it comes to emission readings. Best to have all 4 reading evenly IMO. But hey, to each his own. Your car, your say.

 

My car had a cat problem. The one on the right side was plugged for whatever reason. I noticed a slight lope at idle, and it was a low idle too. I went to the Toyota store and had them run a scan and they confirmed it.

Now I did have a rotten eggs smell too, so that helped me confirm it. If you have to go for cats don't do the Lexus factory ones. That's too expensive at $2K. Mine would have cost about $600 for one, so I just did them both for just under a $1000. Problem solved.

 

going to mechanic on saturday
if one cat is 600 how could you do both for under 1000?

 

If you went aftermarket on cats, you'll end up buying them again in 2 years or less maybe. The guts in those aftermarket things are terribly cheap made. But I hope it lasts you guys longer. OEM is the way. At least for me it is.

 

Mine are Magnaflow's and the shop's had good luck with them - that's why $1K instead of $2K. I didn't buy those cheap online ones if that's what you're talking about.

The shop gave me a bit of break on labor because they had the car up on the hoist anyway so that's why it was better just to do both.

They did have to do a little bit of custom fabrication to make sure they fit exactly but that's what they're known for.

Anyways p***ing around with O2 sensors and going on a goose chase without knowing what's wrong is always a costly exercise I figure..

 

I just had my gaskets done and all 4 o2 sensors replace. The code is from leaking exhaust.. Mine was at the head (exhaust headgasket) : reason toyota seal exhaust with composite gasket and after many miles they fall apart and you develope a slight leak in exhaust system. Do not change the cats you will end up spending more money later. The toyota cats are tough as they come. I would do new o2 and cats gaskets. I would also change the maf sensor. It is very important.