Failed Smog Test Troubleshooting


I have to get my Toyota smogged. Last time it barely passed.
The test said that under the

NO(PPM) max=807 and aver. = 237/i had 738 at 15mph
max=746 and aver. = 199/i had 696 at 25 mph

I am in Calif. What are the least expensive things i can do to help it pass the test? I was told (by a Ferrari mechanic) it might actually do better because the engine it came with when i bought it was relatively new (rebuilt) and it may have adjusted better thru time (20,000 miles later)to the pvc valve. He said he was saying that because it was a possibility…but not necessarily a likelihood.

What do you advise?


Howdy Howard,

In Texas you get 2 chances to pass the test before you really have to spend money and do something about it. Most of the vehicles that I see that fail, a new catalytic converter will mask the problem enough to get a passing score.

I would have to run some tests on your vehicle to be sure, but if you are just wanting to guess at something…then I would have a local muffler shop install an aftermarket converter and cross your fingers. Costs about $225 here in Houston.

I would also change your oil, drive the vehicle on the freeway for 10 minutes before testing and make sure the engine and coolant are good and hot before you test.

Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • Harold

    I love how Toyota showcase their product. From engine up to the outer design, its all amazing. Wish I can have my own car soon.