P0420: What's the likelihood this isn't serious bucks?

What did you use to retrieve P0420?

Whats the current oil consumption between oil changes? High oil consumption leads to an early death of the catalytic converter.

Are you even checking the oil level regularly?

This warning light is NOT a low oil level light! It is a low/no oil pressure light, which is often due to low oil level. Have you seen this light come on, and stay on steadily or intermittently?

If oil consumption is not "high," maybe replace the air/fuel and/or, O2 sensors? If that doesn't solve the problem, then a new CAT may be needed. If so, probably best that those sensors were replaced.

Expensive/Inexpensive is in the eye of the beholder.
To me, a NEW or late model used car is expensive. A NEW Catalytic converter at $1300 (if you DIY) is cheap, esp if you get another 138,000miles out of the car.

Hopefully Pat will chime in.

 

If this were a California car, you would be covered under warranty. Since it's not......Tampaprius in Florida buys cats from ebay for under $100 and has someone weld it on......you can probably do the same in AZ

 

Try some fuel injector cleaner first. I had the P0420 code. Based on researching some posts, I tried fuel injector cleaner. The CEL went out after the next start after driving it around a bit. Don't know if the CEL would have went off on it's own anyway, or the fuel injector had anything to do with it. But, it's been little over a month and 3000 miles and the CEL has not re-appeared yet. I have 220,000 miles and burn ~1 qt every 3000 miles.

 

according to this P0420 Error Code: Catalyst System Efficiency Below Threshold (Bank 1) it could be:

I would check oxygen sensor wire, if not replace spark plugs, get several bottles of cleaner and go for long highway trip.

 

replacing spark plugs ain't gonna help a p0420. I did try "Cataclean" on a corolla and it did nothing but waste $30. for less than the cost of having a shop replace your o2 sensors, you can buy a special o2 sensor socket and replace them yourself-- do it when the engine is cold-- but most likely you will need the cat anyway. btw, some parts stores will lend you the o2 sensor socket.

if you're very lucky, new sensors and some injector cleaner will do the trick, but usually the cat is just bad.

 

If you aren't checking the engine oil level regularly, you should. You'll have a good idea of how much, or little, the engine is consuming. As it begins to consume a lot of oil between oil changes, you can start saving for a used engine replacement, a CAT replacement (which you seem to be requiring now), or another vehicle.

Quite are few horror stories of people who don't check the engine oil level regularly, until the low/no oil pressure warning light comes on, wondering how much damage they have caused when that warning light comes on steadily or intermittently.

Good luck w/ your repair.

 

I'm no expert, but in my personal opinion keeping the fuel injectors, valves, and the whole fuel system clean and efficient is important to keeping the cats, engine, and even the hybrid battery healthy for the long haul. For the first 90k kms of ownership I was using Lucas fuel system treatment. I've been happy with this additive but I have since come to the conclusion that a better product will have pea (polyetheramine). The two products that have very high percentage amounts of this cleaning ingredient, AND include an upper cylinder lubricant are Redline Sl-1 and Gummout Regane. Since using these products I've gotten slightly higher fuel efficiency which I could not achieve with the Lucas fuel treatment. Totally non scientific but both these products do seem to have very high customer reviews and loyalty. Pea is the only known cleaning chemical that can survive through the combustion process.

 

If he drives short distances in cold temps, used non-synthetic oil and has some oil burn that can clog cat and trigger code. Something like Seafoam or Lucas cleaner does not cost much. I would do tune up, cleaner, switch to Top Tier gas, put a tank of premium and go long drive to give cat to burn deposits. And if it doesn't work move to next step - no harm done good luck.

 

I'd put the above in the same category as a blessing from the pope. For starters: what's a "tune up", lol?

 

You entitled to your scepticism but I've seen this work for '03 Camry. You need a scanner to reset code, but it did not come back, it's been over 2 years

 

Yeah I appreciate that the CAT can get clogged by oil, but what's done is done. For example: switching to higher octane fuel will do nothing but lighten the wallet.

 

Just for 1-2 tanks ? Premium burns slower and cases higher cat temps.