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

Intake Air Temperature (IAT) sensor -G42-, checking







Special tools and equipment
- VAG1526 A
- VAG1594 A
- VAG1598/31
- VAS5051 with VAS5051/1

NOTE: The Intake Air Temperature (IAT) sensor -G42- is integrated in the Mass Air Flow (MAF) sensor -G70-.

Test sequence
- Connect testing and information system VAS5051 and select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.







Display on VAS5051:
- Under -1- select diagnostic function "08 - Read measured value block".







Display on VAS5051:
1. Enter display group
- Enter "004" for "display group number 004" in zone -2- and confirm entry by pressing -Q- button.







Display on VAS5051:
- Check indication in display field -4-.







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

Checking wiring







- Disconnect connector (arrow) to mass air flow sensor.
- Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. Wiring and Component Check With Test Box VAG 1598/31







- Check for open circuit and short to positive or ground in following wiring connection:

Connector Test box VAG1598/31
terminal Socket
5 26

- Repair any open/short circuit as necessary.
- Check all wires for short to one another.

If no wiring malfunction is detected:
- Replace Mass Air Flow (MAF) sensor -G70-.