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

1994 Volkswagen Golf (1H1) L4-1.8L (ACC) CanSECTION Testing and Inspection
Intake Air Temperature (IAT) Sensor, checking

^ VAG 1551 Scan Tool (ST) connected Connecting VAG 1551 Scan Tool


- Start engine and let idle.
- Operate VAG 1551 Scan Tool (ST) according to information indicated on display:
^ Rapid data transfer operating mode
^ Address word 01 for "Engine Electronics"

- Indicated on display

[Rapid data transfer HELP ]
[Select function XX ]


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

- Indicated on display

[Read measuring value block HELP ]
[Enter display group number XX ]


- Press button -0- twice to enter display group number 00, and press -Q- button to confirm input.

- Indicated on display
(1-10 = display fields)

[Read measuring value block => ]
[1 2 3 4 5 6 7 8 0 10 ]


Note:
^ If something different is indicated on the display refer to VAG 1551 Scan Tool (ST) operating instructions.
^ If "Error in data transfer" is displayed (caused by an input error) disconnect the cable from VAG 1551, reconnect, and begin the test sequence again.

- Remove Intake Air duct,
- Spray Intake Air Temperature Sensor (G42) with chilling spray (commercially available) and observe value displayed in display field 4.
^ Displayed value must increase

- Press buttons -0- and -6- to select "End Output" function.
- Press -Q- button to confirm input.

If the display/temperature value does not change as specified:
- Carry out electrical testing, test step 14. Pinout Values and Diagnostic Parameters
- If necessary, replace housing for Fuel Injector with Intake Air Temperature Sensor (G42).
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.