Intake Air Temperature Sensor
NOTE:
Intake Air Temperature (IAT) sensor may also be referred to as Manifold Air Temperature (MAT) sensor.
A malfunction in IAT sensor circuit can set a related Diagnostic Trouble Code (DTC). For testing procedure, see appropriate SELF-DIAGNOSTICS article. An out-of-calibration IAT sensor may not set a DTC. Use the following procedure to test sensor calibration.
Disconnect IAT sensor harness connector. Using an ohmmeter, measure resistance of IAT sensor at specified temperatures. See IAT SENSOR RESISTANCE VALUES table. Resistance should be high when air temperature is cold and drop as air temperature warms. With vehicle sitting overnight, ECT sensor and IAT sensor should have close to the same resistance reading. If resistance is not within specification, replace IAT sensor.
IAT SENSOR RESISTANCE VALUES
| Temperature °F (°C) | Ohms |
|---|---|
| 212 (100) | 177 |
| 158 (70) | 467 |
| 104 (40) | 1459 |
| 68 (20) | 3520 |
| 32 (0) | 9420 |
| 5 (-15) | 21,450 |
| -40 (-40) | 100,700 |