Hello,

We have a 2005 Camry. The "check engine light" is on and the code is P0420 ("Catalyst System Efficiency Below Threshold Bank 1"). When I clear this code it comes back after 20-30 miles, so it seems this is not a glitch.

We are in California and the car is up for getting its smog certification again, so we need to take it in to get tested. I'm looking for advice from this forum on the best way to proceed. Should I try to fix the code before I take it in, and if so what would you recommend?

Or should I just test it now, as is, and see if it passes, and then deal with it if it does not pass? Also, is there anything I can do to increase the chances that it will pass, like does it make any difference if the car is warmed up or not before the test?

Thanks!

 

California does a check of the cars ODBII system to determine if it works AND that all the self checks have been done. To pass typically all self checks need to be completed.

When you cleared the P0420 code the computer went into self test mode and when the the test for the converter failed it reset the code.

If you clear the code the cars computer will again go into a self check mode and its readiness check will not be completed. The inspection station finding this will either fail the car or tell you to come back when all the checks have been completed. This typically means driving the car a couple of days.

A check engine light being on is a automatic failure of the test.

 

Thanks! You probably just saved me $50, because I was leaning towards just taking it in "as is" and to see if it passed. I thought they would only test actual emissions and didn't know that the OBDII status was part of the check. So thanks again!

 

Think most states eliminated tail pipe emissions tests for cars having ODBII. Older cars not having ODBII may still have a tail pipe test.

If you change out the converter, make sure you use only a California certified converter. CARB certified is what they may call it. You can only use certified converters to be legal. Inspection stations are supposed to check for this and will flunk the test if using non-certified parts.