P-0420 Catalyst effieciency code

[drcmrn]

I have this P-0420 Catalyst effieciency code that is driving me crazy. i purchased an Eastern Converter and put it in and still the code comes up. i have been told that O2 sensors would give their own error code and i don't know what else to check. Any suggestions? It is a 2003 STS w/ 89K miles

[Texas Jim]

I have this P-0420 Catalyst effieciency code that is driving me crazy. i purchased an Eastern Converter and put it in and still the code comes up. i have been told that O2 sensors would give their own error code and i don't know what else to check. Any suggestions? It is a 2003 STS w/ 89K miles

Check with your dealer about warranty.

Some of the emission stuff, like 02 sensors and converters are covered for 100,000 miles.

I am not sure of the TIME LIMIT...either 6 years or 8 years... I am not sure.

[Ranger]

I believe it is 8 years.

[Cadillac Jim]

The HO2 sensors will throw a code if the heater is burnt out or the connector is loose or off. If either or both of the two on the catalytic converter simply aren't installed, they won't throw a code but you will get the P0420 code. If the new cat didn't have the fittings, he might simply have left the HO2 sensors off the cat but connected. Or, it might not be the right cat, or it might be installed wrong. Over the years I have found that about half the cats I have bought or had installed on warranty have been dropped while still in the box and will fail in a few months, throwing a P0420 code or worse, coming apart and dribbling ceramic dust or particles back into the mufflers.

[drcmrn]

The HO2 sensors will throw a code if the heater is burnt out or the connector is loose or off. If either or both of the two on the catalytic converter simply aren't installed, they won't throw a code but you will get the P0420 code. If the new cat didn't have the fittings, he might simply have left the HO2 sensors off the cat but connected. Or, it might not be the right cat, or it might be installed wrong. Over the years I have found that about half the cats I have bought or had installed on warranty have been dropped while still in the box and will fail in a few months, throwing a P0420 code or worse, coming apart and dribbling ceramic dust or particles back into the mufflers.

thanks, i am going to replace the two forward sensors, hopefully thaat will fix it. new law in Illinois will not allow you to renew plates until it passes an emissions test.