With Manufacturer's Scan Tool

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

Special tools and equipment







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

Test sequence
- Connect VAS5051 scan tool and select the control module for engine electronics using "address word" 01. Engine must be running at idle. Connecting VAS 5051/VAG 1551 Scan Tool (ST)

Display on VAS 5051:







- Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS 5051:







1 - Display group input, max. entered value = 255
- Enter "004" for "display group number 004" in field -2- and confirm entry by pressing -Q- button.

Display on VAS 5051:







- Check Intake Air Temperature (IAT) sensor in display field -4-.

Display Group 004:

- Exit function "08 - Read measured value block" by pressing <- button.

Checking wire connections
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect ECM. Electrical Testing Using VAG1598/31 Test Box







- Disconnect connector to Intake Air Temperature (IAT) sensor -G42-.







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

Harness connector VAG1598/31 test box
Terminal Socket
1 85
2 108

- 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 Intake Air Temperature (IAT) sensor -G42-.

Checking sensor
- Connect multimeter at sensor for resistance measurement.







Specified values

Temperature degree C Resistance k Ohm
-20 approx. 13.8
0 approx. 5.5
20 approx. 2.4
40 approx. 1.1
60 approx. 0.6

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