Air Temperature Sensor ( Ambient / Intake ): Testing and Inspection

Intake Air Temperature (IAT) Sensor -G42-, Checking

Special Tools and Equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAS5051 with VAG5051/1

Test sequence
- Connect VAS5051 tester and select vehicle system "01 - Engine electronics". Engine must run at idle for this. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAS 5051 Tester, Connecting and Selecting Functions" Testing and Inspection







Display on VAS5051:
- Select diagnostic function "08 - Read Measuring Value Block" in selection -1-.







Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "004" in button field -2- for "display group number 004" and press Q button to confirm input.







Display on VAS5051:
- Check Intake Air Temperature (IAT) sensor in display field -4-.

Display Group 004:

- Press "08 - Read Measuring Value Block" to end function <- button.

Checking wire connections
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM), do not connect ECM. Refer to "Scan Tool Testing/Wire and Component Testing Using VAG1598/31 Test Box" Testing and Inspection







- Disconnect connector -1- at Intake Air Temperature (IAT) sensor -G42- (item no.2).







- Check the following wire connections for open circuit and short circuit to Ground (GND) and B+:







- Check both wires to each other for short circuit.
- Repair open circuit or short circuit if necessary.

If no malfunctions are found in wires:

Check sensor:







- Connect multimeter at sensor for resistance measurement.

Specified values







If specified value is not obtained:
- Replace Intake Air Temperature (IAT) sensor.