P0430 Code: Catalyst System Efficiency Below Threshold (Bank 2)

In my case, I installed just one on the driver's side and that did the trick. The idea being 1 is harder to see by an inspector. My best guess is that it depends on how impaired your catalytic converter is. As that degrades you may need to use two. If it is right on the edge (as in my case), one worked. As for installing on the other side, I think there is another code for failure on the passenger side. It probably won't hurt but why fix something that is working?

 

I have a feeling I will be dealing with this soon. Glad to see there is a post about it

 

Yeah... OP screwed up. He only replaced the o2 sensors which likely didn't need replacing. He needed to replace the AFR sensor way up above before the cats.. he had 394,000 miles so I doubt he still has the truck now, but I still felt this important to point out.

Also, when diagnosing failed cat codes there is a reason why they failed and it may not always be the oxygen/ AFR sensors which made them fail. There may be other items upstream of the piping, spark plugs, MAF, poor fuel pressure etc that needs a thorough and proper digital inspection if you want the cats to last otherwise you are just doing guess work and potentially replacing unnecessary parts.

In the OP's case it's highly likely that his sensors were the reason for failure assuming he maintained everything else, but this is something else critical I cannot point out and stress enough.

Check your short and long term fuel trims and do your testing/ make your repairs based on their percentage rates. They always give you the full running condition story.

 

12TRDTACOMA is absolutely correct…. Learn to read your fuel trims and start with MAF sensor, make sure your truck is up to speed with maintenance etc. My taco just turned 300k and runs like a champ.

I’m my case, outside of regular maintenance (plugs, fillers, etc) I had my injectors cleaned professionally (poor spray, one leaking) replaced the MAF, all 02 sensors (really only needed upstream AFR ones, but replaced all for good measure) and later down the line my drivers side cat failed. I installed a couple anti Fowler on the down stream sensor and monitored my cat efficiency on my scanner. Sure enough the readings were much more stable and behaved like the passenger side bank. Fuel trims looked good. Ran it like that for a month, light stayed off. I also decided to replace my exhaust gaskets and peaked into the drivers cat and saw that it was partially melted!!! Any way, I replaced both my cats with some magnaflow ones (not carb certified) removed the anti fowelers and monitored the new cats. 30k miles later, my taco is still happy with no lights and all the readings look great!

To add to this, my brother’s 4Runner (same engine) check engine light came on. This guy does not maintain his truck at all. He’s the kind of guy who fixes something when it comes up. So he took it to two mechanics, got all four 02 sensors replaced, the truck tuned up, cleaned the injectors and still got a running lean code! The mechanic gave up. My brother just dealt with the light for a couple years until he had to smog the car which obviously it was going to fail. He got desperate and asked me to take an look. So i took his 4Runner for a month and I drive a ton for work. I had my taco readings so I used them as a base line. Sure enough his fuel trims were all over the place on both banks. Replaced the MAF sensor (which he claimed he already did) and boom! Fuel trims stabilized and light stayed off. Two weeks later light came back! This time cat efficiency error. I grabbed my anti foweler plugs and went through the same routine I did with my taco. Ended up replacing the cats and 3k miles later the light stayed off.

Lesson here is maintain your truck, get a good scanner (I use blue driver and really like the graphs), and start trouble shooting. You’ll know right away if any improvements come from changing sensors, monitor other sensors to make sure the readings are correct (ie ECT sensor). It took me a while to learn what are good and bad readings from just googling fuel trims etc. My taco is the first vehicle i 100% wrench on my own because it’s so easy to work on so it helps to know your truck.

On a side note. In my Experience with all my vehicles. If you have a lot of miles on your MAF sensor, just replace it. Cleaning it is a joke in my opinion. Maintaining it by cleaning may be another story, but if you’re already having issues, bite the bullet and replace it. I’m sure people get away with cleaning them, but I’m willing to bet the sensor not reading as well compared to a new one.

 

Not an easy task changing out this fuel filter? Kinda makes me wish I had dealership change it out while they were doing my frame.

 

Not really. You need pull the fuel pump which is under the bed. I propped mine up to change the complete assembly. TBH, 200k On that unit and the filter (more like a strainer) was pretty clean. I didn’t bother with an external fuel filter, but doesn’t mean it’s not a good idea.

 

Had a P0430 that would come back pretty quickly if cleared. I just did what this guy said and boom, multiple drive cycles in and code hasn’t came back. The antifoulers are the way to go, thanks for the info!

 

Damn California, FYI you will fail smog with the fouler installed if the smog tech is actually doing their job.. lol

 

OP, can you not replace both sensors with

$49 234-4260 Oxygen Sensor

234-4260? Or are they side specific and need one of 4260 and one of 4261?

 

Downstream after the manifold cat