2009 Toyota Yaris Intake Air Temperature Sensor

Your vehicle doesn't use a separate sensor for intake air temp. It uses the mass airflow (MAF) sensor, the wires to the MAF sensor are black, pink, orange, light green, and gray.

Sorry but none of my sources show which 2 wires specifically are for IAT reading ..but could I ask why you are needing the 2 wires? i'm assuming you are installing a performance chip or something similar? if so than honestly i would suggest trying to get the chip refunded because those chips do NOT work at all on your Yaris.. not worth the trouble or money .

It is hard to increase horse power AND MPG at the same time. Usually when you increase HP the MPG tend to go down. The best and easiest mods to start with for gaining HP is a cold air intake system. The decent to better brands will run around $200 - $300. It lets the engine get more fresh air and usually ups the HP by 3 - 5 to the wheels (although most brands swear it raises HP by 10 - 15, I have never seen a dyno sheet proving that.). Another upgrade would be headers, but once you get into this stuff it can get addicting and start adding up $$ very quickly. If this is just your daily driver honestly I would not do anything to it, I believe the yaris gets around 30 MPG or so stock, that's very good rating considering the average MPG of vehicles on the road today is around 19 MPG. Hope this helps.

There is a division of Toyota called TRD, they sell cold air intakes, headers etc.

These are the ONLY performance products that will not void your warranty.

As Blue said, these chips are a can of worms and will void your factory warranty.

Remember, the Yaris has a 1.5 liter 106HP engine.

The advantage it has is that it only weighs 2311lbs.

There is an ambient temp sensor: