Sensors & outputs Temperature
IAT — intake air temp
MAT, open-element thermistor · sensor · Temperature
Same electrical family as CLT: two-wire NTC, not polarised. Open-element in the intake tract for response. Analog Temp 2.
Typical parts: GM open-element IAT (grommet); GM closed brass IAT; Bosch air-temp NTC
Device pinout
Looking into the sensor. Either cavity is signal; the other is sensor ground.
- Connector: GM weatherpack 2-way or Bosch 2-way
- Layout (looking into the part): A · B; polarising key top
| Device pin | Function | Type | Race Core | TunerStudio |
|---|---|---|---|---|
| A | IAT signal (either pin) | Signal | C30 | Analog Temp 2 |
| B | Sensor ground (other pin) | Ground | C1–C8 / C29 / C31 | Sensor GND |
Wiring notes
- Open-element in the pipe after the intercooler on a turbo car. A closed brass IAT in the manifold reads fuel-cooling and lies after a spray.
- Same GM resistance curve as CLT on most parts. Confirm; some Bosch IATs are a different table.
- Do not share one two-wire sensor between CLT and IAT.
- Combined airbox pressure-and-temperature sensors (Bosch PST air family) are not this two-wire part. See Bosch P+T before you crimp a four-pin connector as if it were an IAT.
Failure modes
- IAT tracks coolant, not the pipe: the sensor is a closed brass element in the manifold, or it is heat-soaked in a dead-end boss.
- IAT and CLT always match: both signals are on one sensor, or the pins are tied together.
- A Bosch air-temp sensor reads tens of degrees off with the GM curve loaded: it is a different resistance table. Confirm before you trim VE to hide it.