As you might already be aware (and if you're not, well that's OK, too)... the intake air temperature (IAT) sensor is part of the mass air flow (MAF) sensor.
The MAF sensor has a total of 5 wires. Three of them are dedicated to the MAF part and the other 2 are dedicated to the IAT Sensor part.
In this ‘How to Test’ tutorial, I'm gonna' show you the easiest way to test the intake air temperature (IAT) sensor.
Here are the main subheadings of this article at a quick glance:
The very first thing you'll notice when the IAT Sensor goes BAD inside the MAF sensor is the check engine light (CEL) shining nice and bright to let you know that there's a problem and that there's a Diagnostic Trouble Code (DTC) stored in the PCM memory.
Here are some of the specific symptoms you'll see/have:
Here's a basic list of tools you'll need:
In a nutshell, the intake air temperature (IAT) sensor helps the PCM (Powertrain Control Module = Fuel Injection Computer) make a correct measurement of the air mass that enters the engine by providing a temperature reading (measurement) of that air.
To get into a little more detail: the PCM needs to know two very important things (among several) to calculate the correct amount of fuel to inject for the amount of air the engine is breathing.
These two things are:
The reason that the PCM needs to know the temperature of the air is because air temperature has a direct effect on air density... and since the MAF sensor can only measure the flow rate of air passing thru' it, the intake air temperature sensor helps the PCM to further ascertain the precise amount of air entering the engine.
This in turn helps the PCM maximize everything from fuel consumption to performance.
OK, these are the circuit descriptions of the Mass Air Flow (MAF) Sensor and the Intake Air Temperature (IAT) Sensor:
|MAF Sensor Connector Pin Out|
|A||Yellow||MAF Sensor Signal Output|
|B||Black w/ White stripe||Chassis Ground|
|C||Pink||12 V. Ignition Fused Feed|
|D||Tan||Intake Air Temp (IAT) Sensor 5 Volts|
|E||Black||Intake Air Temp (IAT) Sensor Ground|
“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”