With Manufacturer's Scan Tool

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

Special tools and equipment






- VAG 1526A
- VAG 1594A
- VAG 1598/31
- VAS 5051 with VAS 5051/1

Test sequence
- Connect the vehicle diagnostic, testing and information system VAS 5051 and select the vehicle system "01 - Engine electronics" from the menu. When doing this the engine should be idling. Connecting VAS 5051/VAG1551 Scan Tool






Display on VAS 5051:
- Select the diagnosis function "08 - Read data block" from the menu -1-.






Display on VAS 5051:
1 - Enter display group
(figures up to 255)
- Using the keypad -2-, enter "004" to select Display group 004 and confirm entry with Q button.






Display on VAS 5051:
- Check display value for intake air temperature sender (display zone -4-):

Display Group 004:

- Press the <- button to exit from the function "08 - Read data block".

Checking wiring connections
- Connect test box VAG 1598/31 to wiring harness for engine control module. Do not connect to the engine control module itself. Wiring and Component Testing Using VAG1598/31 Test Box






- Unplug connector -1 - at intake air temperature sender -G42 -2-.






- Test for open circuit and short to positive or Ground in the following wiring connections:

Connector Test box VAG 1598/31
Contact Socket
1 85
2 108

- Test for short circuits between the two wires.
- Correct any open/short circuit as necessary.

If no malfunction is detected:
- Test intake air temperature sender.

Testing sender






- Connect multimeter (resistance measurement range) to sender.

Specifications:

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

If the specification is not attained:
- Install a new intake air temperature sender.