i bought my tundra in 2004 and it's never failed a smog check. ditto for the 2006 4runnerYeah, that surprised me when I looked it up. It's four years if there's a change of ownership. Not sure of the logic there?
The smog check also includes a tailpipe emission analysis. Smog check places are not allowed to also make repairs so, if it fails, you have to go somewhere else to have it repaired, then pay for a new test.