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 25, Intake Air Temp Sensor CKT/High Temp Indicated
IAT sensor uses a thermistor to control signal voltage to ECM. ECM applies 4-6 volts on Red/Black wire to the sensor. When intake air is cold, sensor resistance is high. ECM will sense high signal voltage. As intake air temperature warms, sensor resistance decreases, and voltage drops.
- Code 25 is set if signal voltage indicates intake air temperature is more than 284°F (140°C), or signal circuit is grounded for 5 seconds. Code 25 will set if sensor or wire is open, or faulty connection exists in circuit.
- If resistance is greater than 14,800 ohms, replace sensor.
| Temperature °F (°C) | Ohms |
|---|---|
| 210 (99) | 200 |
| 160 (71) | 450 |
| 100 (38) | 1300 |
| 70 (21) | 2500 |
| 40 (4) | 5200 |
| 20 (-7) | 8250 |
| 0 (-18) | 14,800 |
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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.