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Home >> GMC >> 1993 >> Forward Control 7.4 N >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Engine Sensors & Switches >> Intake Air Temperature (IAT) Sensor
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Intake Air Temperature (IAT) Sensor

If an IAT sensor-related code is present, see appropriate TESTS W/CODES article in this section. 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 IAT SENSOR RESISTANCE  table. With vehicle sitting overnight, IAT sensor and coolant sensor should have close to the same resistance reading.

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