2004 tundra p0420 bank 1 code - 2002 Toyota Sienna

SOURCE: Pulled code p0420 on 99 chevy astro, 2wd, v6

from what i am finding the code means o2 sensors. they recommend replacing them and if this does not work than replacing the cat converter

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

causes

A code P0420 may mean that one or more of the following has happened:

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Retarded spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings

• Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
• Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
• Inspect the downstream heated oxygen sensor (HO2), replace if necessary
• Replace the catalytic converter

SOURCE: I have a P0420 code catalyst efficiency below

it is a bad converter not o 2 sensor i would change the cat and both o 2 sensors

SOURCE: Getting DTC code P0404 and P0420. What should I do?

The 420 will not go away with egr replacement. it means the computer has detected a problem with the catalytic converter. eGR valve is at the rear of the engine. Not easy to get to on vans.

SOURCE: p0051 code, where is the sensor located, where is

Bank 2 is passenger side, sensor 1 is the one up closest to the exhaust manifold. Plug in type (just remove old and plug back into the wiring harness connector) is about $90 at Autozone. You can get a cheaper one that you splice but it's confusing to understand which wires to splice together. Don't forget to buy the special socket, $10, to remove and install the sensor. It's split up the side for the wires. Forget trying to use an open end wrench, socket is best.

SOURCE: received fault codes P0420 and P1296 catalyst

Not sure on the P1296 code, however in 95% of the cases the P0420 code means the catalytic converter is bad. See P0420 and P0420.com