PO 128 code need help
 

If this isn't the right place to post this, please let me know.

Recently my Honda Civic 2006 LX 1.8l check engine light turned on. Took it to the mechanic and told me the ECT sensor was defective. Cost me 100$ to figure only what the problem is, and was doubting the mechanic. Talked to a couple friends, everyone told me its the thermostat.

I bought a thermostat and a sensor when I went to the store. Tried the sensor, the check engine lamp turned back on after 3 engine start warm ups. So then I knew it wasn't the sensor. So I replaced the thermostat. Same thing happened again. After 3 warm ups the check engine light turn on again.

My prestone level is full. My radiator cooling fans only turn on when the engine is warm enough. I've tested my old thermostat in hot water and a thermometer and it is working perfectly.

After reading around, I've seen that the IAT sensor might be making this error to pop up. Where is this sensor exactly, and is it combined with the MAF as well? How can I test this unit before replacing it?

Any help would be very helpful, as I am getting confused by this. I've ruled out the most common problems and they aren't it.

The car has about 148k on it.

Thanks

A. LeBLanc