P0420 Code

Spend $350 bucks and get a complete bolt in aftermarket cat assembly (48 state) from ebay. Have it mailed to your friends. Drive there and install it. Very, very easy. Can be done in less than an hour. Look at your original assembly, if it is original Toyota, one converter will be stamped GD3 and the other stamped EA6. Cut the pipes off and sell the 2 catalytic converters as a pair on ebay for $600.

 

I'm in the same boat regarding the 0420 code. Has anyone change out the upstream o2 and you didn't have any more issue? I have 196000 miles and it doesn't burn any oil. The code came on today and the car is running good.

 

It’s a Catalytic converter system it’s need to be fixed with a mechanic.

 

???.....This makes no sense at all. Perhaps you should refrain from providing misguided advice. It makes the situation more difficult and confusing for the poster asking questions.

P0420-Catalyst System Efficiency Below Threshold (Bank 1)

1. Gas leakage in exhaust system
2. A/F Sensor (bank 1 sensor 1)
3. Heated oxygen sensor (bank 1 sensor 2)
4. Three-way catalytic converter

sensor 1 is the one mounted in the exhaust manifold between the engine and first cat (upstream cat)
sensor 2 is the one mounted between the upstream and downstream cat.

So yes, this code can very easily be caused by the sensor mentioned in post 3.

Here's the DTC Guide for that code.....

 

You could always try a bottle of cata clean and drive it hard with quarter tank until close to e. Then fill up on premium. It's worked for me in the past.

Posted via the PriusChat mobile app.

 

p0420 has hidden humor. Does anybody know what it is? I never did any drugs of any kind, but I read alot and know what 420 means. This is funny...

Did you know Palladium (catalyst) more than gold? About $2k/oz

 

BTW: high flashpoint solvent in a bottle doesn't fix a Palladium catalyst. Does anybody know if it's cations or anions that electroplate the palladium?

 

What would happen if you kept driving and clearing that code P0420? Because I can't fix it now. But I've had worse gas mileage for a couple months.

 

Out of CA converters are supposed to flunk smog visual examination if they don't have the OE engravings.

I have a new generic ebay cat that passes OBD-II. My 2006's emissions label claims 50-state compliance, so the computer should be calibrated same as yours.

If you get the job done, the scrap value of the old cat will more than pay for the new one, so you're ahead of the game.

A spark plug anti-fouler on the rear oxygen sensor also works for OBD-II, but could fail the smog visual exam.

 

P0420 code comes on for me on my Gen2 when I fail to timely empty catch can (aftermarket install of catch can between PCV valve and throttle plate). Catch can catches spoils that include oil mist, unburned fuel and water condensation. I need to empty 5oz catch can every 1500 miles.