Intake Air Temperature (IAT) Sensor
If an IAT sensor-related code is present, see the appropriate TESTS W/CODES - 7.4L article. An out-of-calibration sensor may not set a trouble code. Use following procedure to test calibration. Disconnect IAT sensor harness connector. Connect ohmmeter between sensor terminals. Sensor resistance should be as specified. See the IAT SENSOR RESISTANCE . With vehicle sitting overnight, IAT sensor and coolant sensor should have close to the same resistance reading.
NOTE:
Intake Air Temperature (IAT) sensor is also referred to as Manifold Air Temperature (MAT) sensor.
IAT SENSOR RESISTANCE
| Temperature °F (°C) | Resistance (Ohms) |
|---|---|
| 210 (100) | 185 |
| 160 (70) | 450 |
| 100 (38) | 1800 |
| 70 (20) | 3400 |
| 40 (4) | 7500 |
| 20 (-7) | 13,500 |
| 0 (-18) | 25,000 |
| -40 (-40) | 100,700 |