Smogcheck failed - Air Temperature Sensor?

[Groer]

Hi,

I recently failed my California Smog Check with my 1993 Camry (2.2l) with high HC, CO and NO values. I already replaced the Oxygen-Sensor and the leaky air intake hose but it's still failing. I get the error code 24 when doing the self diagnostic test, which points me to a defective air temperature sensor. Can this sensor cause all the trouble or must there be something else that's wrong?

Thanks for your help,
Alex

[sam333]

It will make some difference , but I have never seen that alone cause a car to fail smog.

How old is your cat? How many miles on the car? OBD1 cars can really run like crap before you get any codes at all.

[Groer]

Originally Posted by sam333

It will make some difference , but I have never seen that alone cause a car to fail smog.

How old is your cat? How many miles on the car? OBD1 cars can really run like crap before you get any codes at all.

Does it make sense to try changing the air temperature sensor to bring the values a little bit lower? They are just above the limit.

The car has 160k miles and probably still the first cat. Is the cat failing? Is there another easy trick to try?

Alex

[sam333]

The IAT sensor is easy to test , the manual will tell you how. You are just about at the limit of the cat on a good running engine ( no oil or coolant burning).Have you done a complete tune up? Never go into smog with a cold engine/cat, drive it on the freeway for at least 1/2 hour right before your test to get that old cat up to operating temp and make an appointment so its not sitting cooling off.

[hill8570]

Failsafe on that sensor is to assume that the intake air temperature is 68F. If you test in the heat of the day, that's going to give you a slightly rich initial calculation, but the O2 sensors should trim that pretty quickly. Just doesn't seem like it'd be enough to throw off a stink check.