code po 420 need help
 

have a 2003 camry and check engine light came on and scan code po420 look it up and said your cat coverter is the issue. is there another thing i should look for to see what turning on th light? cats are expensive is there another sensor or something else to replace to solve issue?

O2 sensors. Had that, and as well as P0441 coming up on my 2000 Camry LE 4cyl. Replaced the front O2 sensor first, that didn't fix it, and I replaced the second one and that fixed it. Mines 13 years old now and the cat is still working good with new O2 sensors, so I'd imagine yours should be fine too.

If you can get a hold of an OBDII scanner, those can trace the front and rear O2 sensors, you should see the rear one more steady normally. Mine had both fluctuating completely, originally, and when I replaced them the rear one was steady. Could have been that it was only the rear one that was bad, but idk

What engine, V6 or 4-cylinder?

Is the car in California or a California emissions car?

4 cylinder and no on california i here in connecticut

Typically this code means a bad converter.

The computer does not test the converter directly but the exhaust gas before and after using A/F and 02 sensors. It possible but not likely a sensor is bad as these sensors are monitored and have their own codes.

Another possibility is a leak in the exhaust system before the sensor after the converter. An air leak will skew the exhaust gas mixture.

If you have real time ODBII reader that can gain access to these sensors data can be read to indicate if they are working OK. If so and no leaks the converter which is most likely.

For replacements there are Toyota and aftermarket brands. Toyota being much more expensive but the better product in terms of life expectancy.

Given the car is NOT in California you can install any converter.

When looking for converters shop the internet as sites like Parts Geek and Rockauto. If wanting a Toyota brand there are sites hosted by dealers who will sell real Toyota parts at a discount.

If replacing the converter keep in mind it has salvage value as it contains precious metals and is not just scrap metal. An internet search may find the approx value.

thanks for the info, the code pops up after driving for over an hour at 65-70 mph on the highway but never turns on in city driving. will check for leaks first before doing the replacement of cat. funny thing is before i purchase the cars from my elderly parents it passed connecticut emissions

The computer runs a preset program to test the converter. Once engine warm, one part of the test takes at least 10 minutes at 40- 70 MPH. The test needs to be run twice, each on separate occasions.