I need some suggestions!!! Please help!

I just recently bought a 1995 Saturn SC2. The "service engine soon" light has been on since I bought the car. I've had my friend (a mechanic) work on the car. He's read the codes and the only one that comes up is for the IAT sensor. He replaced it, along with the O2 sensor and the vacuum tube, and changed the oil and filter. He disconnected that battery and the light is still on. After pulling the codes a 2nd time, the IAT sensor is still coming up. Everything seems connected properly, all the fuses seem to be working, and the car runs fine.

Anyone have any ideas? I need to get the car smogged, but have found no one will run the test with the light on.

 

sit in the drivers seat and turn the ignition from off to run --repeat this 50 times (without starting the car). (no I'm not joking -- this actually works)

This will clear the codes and turn off the SES.

Then drive around and see if the codes return.