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

Special Tools, Testers And Auxiliary Items:
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
- VAG 1598/18 Test Box
- Fluke 83 multimeter
- VW 1594 adaptor 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:

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 0, 0 and 7 buttons to select "display group 7"
- Press Q button to enter input
Display will appear as shown:

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

If implausible value appears in display zone 3 or a substitute temperature of 136.8°C is displayed, check Intake Air Temperature sensor and sensor wiring as follows:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "end data transfer"
- Press Q button to enter input
- Switch OFF ignition





- Disconnect harness connector -1- from Intake Air Temperature sensor -2-
- Measure resistance between sensor terminals





Specification, see diagram
Scale A shows resistance values for temperature range 0 to 50°C
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 sensor G72
- Display the readiness code

If DTC memory was erased:
- Create readiness code again

If specification obtained:





- Connect Test Box VAG 1598/18 to ECM harness connector





- Check wiring for open circuit between Test Box and the connector using wiring diagram:
terminal 1 + socket 64
terminal 2 + socket 33
Wire resistance: 1.5 Ohms maximum

Also check wires for shorting to one another
Specification: Infinite Ohms

If wiring OK:
- Replace Diesel direct injection system ECM J248
- Display the readiness code

If DTC memory was erased:
- Create readiness code again