I have a 2005 Toyota Camry V6.

The check engine light was on for while and I cleared it once using an OBD2 reader. It didn't come up for while. I used the .87 petrol and I thought that is what causing the issue. So I mixed some premium gas and the check engine light got turned off. Now I'm still with same gas mixture and the check engine light is turned on. I couldn't find the issue since the drive on my car is smooth.

I read the error code using a odb2 reader and P0430 was the error code. I checked a couple of places online but couldn't really find what could be the issue might me.

I have replaced Spark plugs, Air filter, PCV valve, transmission oil and engine oil.

Attachment : these are the reading from my car (did a freeze frame and took picture of the error. Any suggestions/opinions are welcomed.

enter image description here OBD2 reader

2 Answers 2


While in theory this could be caused by a faulty O2 sensor reporting invalid data, I believe it is more typical for this kind of error to actually be what it says, i.e. catalyst system efficiency is below threshold.

Have you replaced your catalytic converter? Is it original or aftermarket? I would start the diagnosis by trying to replace the cat. Yes, it is more expensive than changing your engine oil, but then again it's more likely to fix the error code permanently.

A faulty catalytic converter will not result in a non-smooth ride. The engine works perfectly with a degraded catalyst.

  • Thanks for your reply. One thing I noticed is, if I use .87 petrol.. pick up of the car goes down.. I think it is original, I don't think it is replaced before at all.. How do you find if oxygen sensor is bad ..? I read it online and some one was saying there might be some hose leak..? is that possible ? Sep 13, 2017 at 15:11
  • Typically, if an oxygen sensor is bad, it will have its own error code, so I believe in your case the most likely culprit is the catalytic converter. I think I got the code P0136 when my O2 sensor failed. So I would replace the cat first, only then the O2 sensors.
    – juhist
    Sep 13, 2017 at 15:18
  • 2
    a lot of shops get burned by throwing a convertor at a car especially when they cost $1k+. @still_learning should confirm fuel trims, check for exhaust leaks and graph the b2s2 activity before throwing a convertor at the car.
    – Ben
    Sep 13, 2017 at 16:21
  • Ah, exhaust leak, forgot that one from the list. @Ben, I guess the fuel trim and bank 2 sensor 2 activity are for testing whether the problem is in the O2 sensor?
    – juhist
    Sep 13, 2017 at 16:27
  • yes on a bad convertor the rear o2 will switch between rich and lean. an exhaust leak causes switching with pin hole leaks. larger leaks will force the o2 lean. generally good values at idle and cruise sit around 600-700mV.
    – Ben
    Sep 13, 2017 at 16:31

I've had this error on two Honda Civics, new cat resolved them both. I was able to mail order new cats for less than $100 each. Got $75 from the recycler when I turned the old one's in.

If you have a jack, jackstands, and basic tools (screwdrivers, ratchet set) you should be able to replace it yourself, if you like.

Borrowed an O2 sensor socket from the local autoparts store.

Best of luck!

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