Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Intake Air Temperature Sensor
The Intake Air Temperature (IAT) sensor is a variable resistor, sometimes called a thermistor. The IAT sensor measures the temperature of the air entering the engine. The ECM supplies 5 volts to the IAT signal circuit. When IAT sensor is cold, sensor resistance is high. When air temperature increases, sensor resistance lowers. With high sensor resistance, ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, ECM detects a lower voltage on IAT signal circuit. If ECM detects an out of range voltage in the IAT signal circuit, a DTC will set. To diagnose, see SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO - DIESEL article.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.