Test IAT - Intake Air Temperature Sensor
| Circuit | Breakout Box Pin No. | PCM Pin | Wire Color |
|---|---|---|---|
| IAT | 25 | 2K | Black/Red |
| GND | 46 | 3D | Black/Blue |
1) Check System Integrity Visually check all wiring, connectors and components for evidence of damage, shorting or looseness. If a fault is found, repair as necessary. If no fault is found, go to next step.
2) Check IAT Resistance Turn ignition off. Install breakout box, leaving PCM disconnected. Access IAT sensor. The sensor is located in the Measuring Core-Volume Vane Airflow (MC-VAF) meter. Monitor temperature at the IAT sensor using Rotunda Digital Thermometer (055-00100). Measure resistance between IAT and GND test pins at breakout box. Compare readings with RESISTANCE SPECIFICATIONS (IAT SENSOR) table. If resistance is not as specified, go to next step. If resistance is as specified, IAT circuit is okay. If no other problem or code is found, replace PCM.
| Temperature °F (°C) | Ohms |
|---|---|
| -4 (-20) | 10,000-20,000 |
| 32 (0) | 4,000-7,000 |
| 68 (20) | 2,000-3,000 |
| 104 (40) | 900-1,300 |
| 140 (60) | 400-700 |
3) Check For Open IAT Wire Ensure ignition is off, breakout box is installed and PCM is disconnected. Disconnect MC-VAF sensor connector. Measure resistance between IAT test pin at breakout box and IAT terminal at VAF, MC-VAF or IAT sensor connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open IAT wire.
4) Check For Short In IAT Wire Ensure ignition is off, breakout box is installed and PCM is disconnected. Measure resistance between ground and IAT test pin at breakout box. If resistance is more than 10,000 ohms, go to next step.
5) Check IAT Sensor Ground (2.5L) Ensure ignition is off. Measure resistance of GND wire between ground and IAT terminal at MC-VAF sensor connector. If resistance is less than 5 ohms, replace MC-VAF sensor. If resistance is 5 ohms or more, repair IAT GND wire.