presistant p0420 code 2002 tacoma

changed both 02 sensors and cat still getting this code. between 50 and 70 miles of reseting. any ideas ? is this a common problem ? thanks for any help

 

mine tripped a week ago

i found out certain brands of gasoline trip my sensors, especially shell gasoline, burn off your tank and refill with a different station/grade it may be an additive in the gasoline

 

try running a fuel system cleaner through your truck at your next fill-up

 

That code is telling you that the ECU has diagnosed that the catalytic converter is worn out and needs to be replaced. It is not a problem with the O2 sensors.

The cat is covered under the federally mandated emmissions warranty for 8 years or 80,000 miles. If you fit into that range, drive into your local dealer and have them install a new cat for you.

Or;

http://www.urdusa.com/index.php?cPath=66_170&osCsid=l4vuevhaeafq00s7mc7ecesoa7

G

 

the cat was changed already. i have checked for leaks. the sensors were changes because they werent reading properly with a scan tool. i thought that would have fixed it. went a head and replaced one of the cats which looked healthy. and the code still keeps coming up .

 

PS that simulator is niceeeeeeeeeeeeeeeeeeeeeee lol

 

Yeah, a P0420 is a generic "catalytic efficiency" code. The computer gathers data from the upstream and downstream O2 sensors and compares them. The downstream should have a steady oxygen level, while the upstream O2 levels should wave up and down. When the downstream exhaust reads the same as the upstream, it indicates the cat isn't doing it's job. And, it takes 50-70 miles after resetting the computer for it to complete a full system check of the emission system.

 

front cat yes rear cat not OEM