Circuit/System Description
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
The sensors listed below are integrated within the multifunction intake air sensor:
- IAT sensor 1
- IAT sensor 2
- Humidity sensor
- MAF sensor
- BARO pressure sensor
The intake air temperature (IAT) sensor 1 is a variable resistor that changes the voltage on the engine control module (ECM) supplied 5 V signal circuit. The signal varies with inlet air temperature in the sensor bore and is displayed by the scan tool as °C (°F). The IAT sensor 2 and the humidity sensor share the same circuit. The IAT sensor 2 signal is displayed by the scan tool as Hertz (Hz) and °C (°F).
The sensors listed below share an ECM supplied 5 V reference circuit:
- IAT sensor 2
- Humidity sensor
- Barometric pressure (BARO) sensor
The sensors listed below share an ECM supplied low reference circuit:
- IAT sensor 1
- IAT sensor 2
- Humidity sensor
- Barometric pressure (BARO) sensor
IAT Sensor 1 - Temperature, Resistance, Voltage Table
| IAT Sensor 1 | IAT Sensor 1 Resistance | IAT Sensor 1 Signal Voltage |
|---|---|---|
| Cold | High | High |
| Warm | Low | Low |
IAT Sensor 2 - Temperature, Frequency Table
| IAT Sensor 2 | IAT Sensor 2 Frequency | IAT Sensor 2 Temperature |
|---|---|---|
| Cold | 45 Hz | -40°C (-40°F) |
| Warm | 302 Hz | 104°C (219°F) |