Intake Air Temperature Sensor, Checking

Intake Air Temperature Sensor, Checking

Special tools, testers and auxiliary items required

• (VAG1526A)

• (VAG1594A)

• (VAG1598/31)

• (VAS5051) with (VAS5051/1)

• 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 ). Refer to => [ VAS 5051, Connecting and Select Functions ] VAS 5051, Connecting and Select Functions 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 -.





* If a temperature is displayed which deviates greatly from the ambient temperature of the sensor, check sensor and sensor wiring for terminal resistances and open circuit.

- Exit function "08 - Read measured value block" by pressing arrow 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. Refer to => [ Wiring and Component Check with Test Box VAG 1598/31 ] Wiring and Component Check With Test Box VAG 1598/31.

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









- 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).