No check engine light but failed emission
 

tried to inspect car. failed emission but had no check engine light. The mechanic said that I have to drive the car so the memory of the cpu will clear.

failed notice was Catilayic and evaporation.

But no light on dash

Is this true?

Make sure the cats is nice and hot when the car gets to the machine. it happened to me in the past at least twice with a 4Runner. From the testing center to the mechanic everything was great because the cat was hot. While waiting inline at the inspection center the cats would cool off and emission values went up. The third time I kept the engine revved up while waiting and it passed with flying colors. All three times done in the same day with no engine tweaking.

how long did you drive or let it idle for. I was told to drive low speed about 30 mph but in low gear to hight rev the engine.

I kept the engine running while waiting and revved it on occasion while waiting because the line was long (maybe 20 minutes or so) idling the engine won't do the trick, you need to make those babies sweat so don't be afraid to rev the car specially if your waiting time is short.

When I lived in Calif I always put mine on the freeway for 20 min at highway speeds before a smog check.

If it i9s failing the "readiness" you need to drive it a few days after any codes are cleared.


It has nothing to do with how it was driven in the few min before the test.