With Manufacturer's Scan Tool

Intake Air Temperature (IAT) Sensor -G72-, Checking

Special tools
- VAG 1551/1552 Scan Tool using VAG 1551/3 Adapter cable
- VAG 1598/22 Test Box (MY 1999)
- VAG 1598/31 Test Box (from MY 2000)
- Fluke 83 multimeter
- VW 1594 Adapter kit
- Wiring diagram

Test sequence
- Connect VAG 1551/1552 Scan Tool.
- Start engine and let idle.
- Press 0 and 1 buttons to select Address word 01: "Engine electronics"

Display will appear as shown (example only)


038906018M 1.9l R4 EDC 00AG 1813 ->
Coding 0001 WSC XXXXX


- Press -> button.

Display will appear as shown


Rapid data transfer HELP
Select function XX


- Press 0 and 8 buttons to select Function 08: "Read measuring value block".
- Press Q button to enter input.

Display will appear as shown


Read measuring value block HELP
Input Display group number XXX


- Press buttons 0, 0 and 7 to select "Display group 7".
- Press Q button to enter input.

Read measuring value block 7
15.4 °C 15.9 °C 16.7 °C

Display will appear as shown

If an unrealistic value appears in Display zone 3 or a substitute temperature of 136.8 °C is displayed
- Check Intake Air Temperature (IAT) Sensor -G72- and wiring to sensor as follows:
- Press -> button.

Display will appear as shown


Read measuring value block HELP
In put Display group number XXX


- Press 0 and 6 buttons to select Function 06: "End output".
- Press Q button to enter input.
- Switch OFF ignition.







- Disconnect -G72- harness connector:
Component locations overview.
- Measure resistance between sensor terminals 1 + 2.







Specification chart
Scale A shows resistance values for temperature range 0 to 50 °C and scale B the values for temperature range 50 to 100 °C.

Examples:
- 30 °C corresponds to a resistance from 1500 to 2000 Ohms
- 80 °C corresponds to a resistance from 275 to 375 Ohms

If specification not obtained
- Replace Intake Air Temperature (IAT) Sensor -G72-.
- Display the Readiness code Monitors, Trips, Drive Cycles and Readiness Codes

If DTC memory was erased
- Set the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specification obtained







- Connect VAG 1598/22 (or 1598/31) Test Box to ECM wiring harness.







- Check wiring between Test Box and connector for open circuit using Wiring diagram.
- Terminal 1 + socket 25
- Terminal 2 + socket 13
Wire resistance: maximum 1.5 Ohms
- Check wires for short to one another, to Ground and to Battery +
Specification: Infinity Ohms

If wiring OK
- Replace Engine Control Module - J248-.
- Display the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If DTC memory was erased
- Set the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes