With Manufacturer Scan Tool

Intake Air Temperature Sensor, Checking

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551/1552 Scan Tool using VAG 1551/3 Adaptor cable
- VAG 1598/22 Test Box
- Fluke 83 multimeter
- VW 1594 Adaptor kit
- Wiring diagram
- Chilling spray (commercially available)


NOTE:
If sensor or connecting wiring is faulty, the Engine Control Module operates with a substitute temperature of 19.5 °C.
Vehicles with engine code AEG; the Intake Air Temperature sensor is a part of the Mass Air Flow sensor G70 and cannot be replaced by itself.

Test sequence
- Connect VAG 1551/1552 Scan Tool. [1][2][3][4]Reading and Clearing Diagnostic Trouble Codes
- Switch ON ignition.
- Press 0 and 1 buttons to select "Engine Electronics" address word 01.

Indicated on display (example only)


06A906018AB Motronic M5.9.2 HS V06 ->
Coding 00000 WSC 00000


- Press -> button.

Indicated on display

Rapid data transfer HELP
Select function XX


- Press 0 and 8 buttons to select "Read Measuring Value Block" function 08.
- Press Q button to enter input.

Indicated on display


Read measuring value block
Input Display group number XXX


- Press 0, 0 and 4 buttons to select "Display group 4."
- Press Q button to enter input.

Indicated on display (1 to 4 = Display fields)


Read measuring value block 4 ->
1 2 3 4


- Note Intake Air Temperature value in Display field 4.







Evaluating Display Group 4







Check continuation when display = approx. -46 °C







- Disconnect 5-pin harness connector -1- from Mass Air Flow sensor -2-.
- Bridge connector terminals 1 + 3 using jumper wires from VW 1594 adaptor kit and observe display.

When display is approx. 141 °C
- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.
- Replace Mass Air Flow sensor G70.

When display is approx. -46 °C:
- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.
- Check wiring using Wiring diagram

Check continuation when display = approx. 141 °C







- Disconnect 5-pin harness connector -1- from Mass Air Flow sensor -2-.

When display is approx. -46 °C
- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.
- Replace Mass Air Flow sensor G70.

When display is approx. 141 °C:
- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.
- Check wiring using Wiring diagram

Check continuation when display = ambient temperature
- Remove intake hose between Mass Air Flow sensor and Throttle Control Module.
- Note Intake Air Temperature value in Display field 4.
- Spray sensor -arrow- with commercial chilling agent while observing temperature value in Display field 4.
- Temperature value must decrease.
- Press -> button.







Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.
- Check wiring using Wiring diagram.

Wiring, checking







- Connect VAG 1598/22 Test Box to ECM wiring harness.







- Disconnect 5-pin harness connector -1- from Mass Air Flow sensor -2-.
- Check wiring for open circuit between Test Box and 5-pin harness connector -1- using Wiring diagram.
Terminal 1 + socket 40
Terminal 3 + socket 12
Wire resistance: max. 1.5 Ohms

- Check wiring for short circuit to Battery +.
- Specification: Infinity Ohms

If wiring OK:







- Measure resistance at Intake Air Temperature sensor G42 terminals 1 (signal) and 3 (Ground).







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

Examples:
- 30 °C (range A) corresponds to a resistance of 1.5 to 2.0 kohms
- 80 °C (range B) corresponds to a resistance of 275 to 375 ohms

If specification not obtained:
- Replace Intake Air Temperature sensor G42.
- Display the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- If DTC memory was erased or if the ECM was disconnected from Battery + , set the Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If wiring OK and resistance measurement values OK
- Replace Engine Control Module.