Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Intake Air Temperature Sensor, Checking: Notes
NO MAF
The Manifold Absolute Pressure sensor and the Intake Air Temperature sensor are combined as a unit and are serviced as an assembly.
Use only gold-plated terminals when servicing terminals in the electrical harness connector of the MAP / IAT sensor -G71 / G42-.
Special Tools And Workshop Equipment Required
- multimeter.
- Wiring diagram.
Test Procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK
Start Diagnosis
-- Connect the scan tool.
-- Engine must be at Room Temperature.
-- Switch the ignition on.
-- Using the scan tool, check the intake air temperature:
| Diagnostic text | Specified value | |||
|---|---|---|---|---|
| Intake Air Temperature (IAT) | approx. ambient air temperature | |||
If the specified value was obtained:
-- Fault is intermittent. Check for proper connection, damaged wiring or loose terminals.
If the specified value was Not obtained:
Checking internal resistance
-- Disconnect the MAP / IAT sensor -G71/G42- electrical harness connector.
-- Using a multimeter, check the MAP / IAT sensor -G71/G42- terminals 1 to 2 for resistance.
Use the chart below for the specified values:
Specified values:
| IAT Temperature vs Resistance | ||
| Temp (C) | min. value ohms | max value ohms |
| - 40 | 31811 | 37560 |
| - 35 | 22941 | 26863 |
| - 25 | 12415 | 14289 |
| - 15 | 6958 | 7880 |
| - 5 | 4036 | 4495 |
| 0 | 3120 | 3442 |
| 5 | 2422 | 2655 |
| 15 | 1519 | 1623 |
| 25 | 968 | 1031 |
| 35 | 629 | 676 |
| 45 | 419 | 455 |
| 55 | 286 | 314 |
| 65 | 195 | 217 |
| 75 | 136 | 155 |
If the specified value was Not obtained:
-- Replace the MAP / IAT sensor -G71 / G42-.
If the specified value was obtained:
-- Continue the test according to the following table:
| Indicated | Cause | Test |
|---|---|---|
| Between -39 to 139 °C | Component or wiring | INTAKE AIR TEMPERATURE SENSOR, CHECKING |
| -40 to -46 °C | Open circuit or short circuit to (B+) | INTAKE AIR TEMPERATURE SENSOR, CHECKING |
| 140 °C | Short circuit to Ground (GND) | INTAKE AIR TEMPERATURE SENSOR, CHECKING |
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.