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.
Code 24 (PRIZM) - Intake Air Temperature Sensor, Open Or Shorted Circuit: Notes
Intake Air Temperature (IAT) sensor is a thermistor in series with a fixed resistor in ECM. IAT sensor measures temperature of air entering intake manifold. ECM applies 5 volts to IAT sensor. ECM monitors voltage across IAT sensor and converts it into temperature reading. When outside air temperature is cold, IAT resistance is high. When outside air temperature is warm, IAT resistance is low. Therefore, when air temperature is cold, ECM will receive a high voltage input. When air temperature is warm, ECM will receive a low voltage input. Code 24 will set if voltage input at ECM indicates either a very low or very high air temperature for at least .5 second.
- Checks for open or short to ground in Yellow/Black wire between ECM and IAT sensor, and a faulty ECM.
- Checks for open in Brown wire between ECM and IAT sensor, and a faulty ECM.
- Determines if problem is a faulty IAT sensor or ECM.
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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.