Operation CHARM: Car repair manuals for everyone.
Home >> Volkswagen >> 2002 >> New Beetle GLS (1C1) L4-2.0L (AZG) >> Repair and Diagnosis >> Sensors and Switches >> Sensors and Switches - Powertrain Management >> Sensors and Switches - Computers and Control Systems >> Air Temperature Sensor ( Ambient / Intake ) >> Testing and Inspection >> With Manufacturer Scan Tool

With Manufacturer Scan Tool




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


NOTE: The intake air temperature sensor (G42) is a part of the Mass Air Flow (MAF) sensor (G70) and cannot be replaced individually.


Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter VAG 1715
- Adapter set V.A.G 1594
- Wiring diagram
- Chilling spray (commercially available)

Test sequence
- Connect scan tool VAG 1551 (V.A.G 1552). Then switch ignition on and select engine control module with the "Address word" 01.

Connecting scan tool and selecting engine control module. [1][2][3]Connecting VAG 1551 Scan Tool

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q button.

Indicated on display


Read Measuring Value Block
Input display group number XXX


- Press buttons 0, 0 and 4 for "Display group number 4" and confirm entry with Q button.

Indicated on display (1-4 = Display zones)


Read Measuring Value Block 4 ->
1 2 3 4


- Read intake air temperature value in display zone 4.
Specification: approx. ambient temperature

If the specification is not obtained:
- Perform check according to following table:







If the specification is obtained:
- Remove Mass Air Flow (MAF) sensor with intake air temperature sensor. Attach connector again.
- Note intake air temperature value in display zone 4.







- Spray sensor -arrow- with commercial chilling agent while observing temperature value. Temperature value must decrease.
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.

Continuation of check when display reads approx.-40 °C:







- Disconnect 5-pin connector off Mass Air Flow (MAF) sensor (G70) and intake air temperature sensor (G42) -arrow-.







- Bridge connector terminals 1+3 using auxiliary cables from V.A.G 1594 and observe display.

If display jumps to approx. 140 °C:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
- Replace intake air temperature sensor (G42)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

If display remains at approx. -40° C:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
- Check wiring using wiring diagram

Continuation of check when display approx. 140° C:







- Disconnect 5-pin connector off Mass Air Flow (MAF) sensor (G70) and intake air temperature sensor (G42) -arrow-.

If display jumps to approx. -40 °C:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
- Replace intake air temperature sensor (G42)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

if display remains at approx. 140 °C:
- Press -> button.
- Press buttons 0 and 6 for function "End output" and confirm entry with Q button.
- Switch ignition off.
- Check wiring using wiring diagram.

Checking wiring
- Remove inner plenum chamber cover, left:







- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module is not connected by this action.







- Disconnect 5-pin connector off Mass Air Flow (MAF) sensor (G70) and intake air temperature sensor (G42) -arrow-.







- Check wiring for open circuit between test box and 5-pin connector using wiring diagram.
Terminal 1 and test box socket 26
Terminal 3 and test box socket 27
Wire resistance: max. 1.5 Ohms
- Additionally check wires for short to one another.
Specification: Infinity Ohms
- Check wiring additionally for short circuit to battery positive or Ground.
Specification: Infinity Ohms

If no wiring malfunctions are detected:







- Perform resistance measurement at intake air temperature sensor(G42) terminals 1 (signal) and 2 (Ground).







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 is in range A and corresponds to a resistance of 1.5 to 2.0 k Ohms
- 80 °C is in range B and corresponds to a resistance of 275 to 375 Ohms

If the specification is not obtained:
- Replace intake air temperature sensor (G42)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

If there is no malfunction in the wiring and the resistance measurement values are OK:
- Replace engine control module.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Reading Diagnostic Trouble Codes
pro multis · About Operation CHARM