Question on a couple of codes my taco is coming up with

My check engine light just came on in my 05 Pre runner SR5 at about 63k miles. I scanned it with my OBDII scanner and two codes came out.
#1 P0420 (Catalyst Efficiency Below Threshold Bank 1)
#2 P0430 (Catalyst Efficiency Below Threshold Bank 2)

When it came on, the performance with the truck had not been affected. I'd like to know what these codes mean and is it an emergency to fix it ASAP??? Any comments would be appreciated. I have since erased the code with my scanner and check engine light turned off. It hasn't turn back on yet...

Thanks...

 

its saying that both sides of your cat converters are bad. I vote bs. If I could remember where the. 02 sensors were I could tell you if all were accused bad.'

there must be another problem. any engine mods done?

 

No modifications done at all. Just came out all of a sudden...

 

Could be caused by an exhaust leak in between the upstream and downstream O2 sensors. Or code could be an error. If the code doesn't come back don't worry about it. If it does then it is time to start checking things out. With low mileage like yours I would not think that the cats could be bad.