Problem with my 2006 Buick Lucerne CXS
Engine size = 4.6 Northstar V8 (y)
Question = 5 plug wires for IAT, need help decoding the colors of the wires.


Answer: The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the signal circuit.


The IAT is internal to the Mass Airflow Sensor. The unit is usually just refereed to as the MAF, or MAT/IAT. The wire colors are as follows.

  • Blk/wht- sensor ground
  • Tan/DkBlue- low reference to ECM
  • Pnk/Blk- fuse sensor supply voltage
  • Tan- IAT sensor signal
  • Tn/Yel- MAF sensor signal


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