Check Engine Light - 2001 Corolla

Here's the latest.

I found a friend with a code reader that could also read the voltage of the two oxygen sensors with a graphical readout. It looked like both sensors were working OK. I reset the CEL 2 times, but the P0420 code continued to return within 40 miles. I called a Toyota dealer and found out the catalytic converter was still covered under the 80,000 mile warranty ( the oxygen sensors are no longer covered). The dealer is convinced it's the catalytic converter and is going to replace under warranty.

I got the impression that P0420 is almost always a catalytic converter issue.

Thanks for your help.

Last year, my 2001 Corolla CE 3-speed auto experienced the same problem (code 420), and the Dealer fixed it (changed the cat. convertor) under the California Emission Warranty (since I live in California).

Everything looks great so far. No problem.

Just to let you know, I believe the Federal Emission Warranty is different from California Emission Warranty. But you said that you have about 50K miles, so that's not really an issue.

- uchok00

Need advice! I am getting P0420 on TOYOTA Corolla 2000 (90K miles).We went for a long drive and drove 852 miles since Friday to Sunday; mostly on interstate and partially (20-30 miles) on highways in hills. Drove around 600 miles. Then while returning home the car was running out of gas (Orange red light started showing up.) We passed an exit without filling gas, because the gas brand there was not known to us. Unfortunately there was no gas exit for a while. Bottom line we drove with orange (low gas) sign on for 20 to 30 miles. After refilling the gas continued journey and after a while got CEL with code P0420.

I went through forums saying about problem with O2 sensors and cat converters. Don't really want to pay $1000 to replace cat. Not sure how to start. Can overdriving cause it OR driving few miles with low gas (orange sign) on?

Can someone please advice on how to go about it? (I have replaced MAF sensor a year ago. Car gives same mileage 37 to 38 mpg in my last trip. Temp gauge behaves normally indicating ECT sensor is probably ok. I made sure that gas tank cap is tight. After first seeing CEL, drove around 100 miles on Interstate and 15 miles in city, drives normal but CEL is still on. I am going to clean the code and try if it reappears, will post the result. ) Till then any comments from experts are most welcome.

Need advice! I am getting P0420 on TOYOTA Corolla 2000 (90K miles).We went for a long drive and drove 852 miles since Friday to Sunday; mostly on interstate and partially (20-30 miles) on highways in hills. Drove around 600 miles. Then while returning home the car was running out of gas (Orange red light started showing up.) We passed an exit without filling gas, because the gas brand there was not known to us. Unfortunately there was no gas exit for a while. Bottom line we drove with orange (low gas) sign on for 20 to 30 miles. After refilling the gas continued journey and after a while got CEL with code P0420.

I went through forums saying about problem with O2 sensors and cat converters. Don't really want to pay $1000 to replace cat. Not sure how to start. Can overdriving cause it OR driving few miles with low gas (orange sign) on?

Can someone please advice on how to go about it? (I have replaced MAF sensor a year ago. Car gives same mileage 37 to 38 mpg in my last trip. Temp gauge behaves normally indicating ECT sensor is probably ok. I made sure that gas tank cap is tight. After first seeing CEL, drove around 100 miles on Interstate and 15 miles in city, drives normal but CEL is still on. I am going to clean the code and try if it reappears, will post the result. ) Till then any comments from experts are most welcome.

Driving 20 or 30 miles with the orange "Low fuel" light on is not a problem.

 

You may have picked up some sediment from the bottom of the fuel tank.

Try resetting the computer and see if the fault code comes back.

Usually a permanent fault code of P0420 does result in an O2 sensor or catalytic converter change.

Need advice! I am getting P0420 on TOYOTA Corolla 2000 (90K miles).We went for a long drive and drove 852 miles since Friday to Sunday; mostly on interstate and partially (20-30 miles) on highways in hills. Drove around 600 miles. Then while returning home the car was running out of gas (Orange red light started showing up.) We passed an exit without filling gas, because the gas brand there was not known to us. Unfortunately there was no gas exit for a while. Bottom line we drove with orange (low gas) sign on for 20 to 30 miles. After refilling the gas continued journey and after a while got CEL with code P0420.

I went through forums saying about problem with O2 sensors and cat converters. Don't really want to pay $1000 to replace cat. Not sure how to start. Can overdriving cause it OR driving few miles with low gas (orange sign) on?

Can someone please advice on how to go about it? (I have replaced MAF sensor a year ago. Car gives same mileage 37 to 38 mpg in my last trip. Temp gauge behaves normally indicating ECT sensor is probably ok. I made sure that gas tank cap is tight. After first seeing CEL, drove around 100 miles on Interstate and 15 miles in city, drives normal but CEL is still on. I am going to clean the code and try if it reappears, will post the result. ) Till then any comments from experts are most welcome.

Driving 20 or 30 miles with the orange "Low fuel" light on is not a problem.

 

You may have picked up some sediment from the bottom of the fuel tank.

Try resetting the computer and see if the fault code comes back.

Usually a permanent fault code of P0420 does result in an O2 sensor or catalytic converter change.

Sounds correct. Yesterday after posting above issue, I left the office and the CEL had gone on its own. Thank God! Probably loose fuel tank cap or driving with low fuel for a while might have triggered it.

Here's the latest.

I found a friend with a code reader that could also read the voltage of the two oxygen sensors with a graphical readout. It looked like both sensors were working OK. I reset the CEL 2 times, but the P0420 code continued to return within 40 miles. I called a Toyota dealer and found out the catalytic converter was still covered under the 80,000 mile warranty ( the oxygen sensors are no longer covered). The dealer is convinced it's the catalytic converter and is going to replace under warranty.

I got the impression that P0420 is almost always a catalytic converter issue.

Thanks for your help.

A p0420 code with so few miles? Keep an eye on the oil level. Some '01 Corollas consume more oil than others which can in turn ruin a catalytic converter.