Intake Air Preheating, Checking

Intake Air Preheating, Checking

Special tools and equipment







- Hand vacuum pump VAG 1390

Test conditions
- Regulating flap vacuum unit not leaking

Checking regulating flap
- Remove air cleaner upper section and filter element.
- Position air cleaner upper section so that regulating flap in air cleaner lower section is visible.
- Connect hand vacuum pump VAG 1390 to vacuum line to vacuum unit.







- Operate pump and check ease of movement of regulating flap and function of vacuum unit.
Regulating flap must close off cold air intake -1-

Checking temperature regulator
- Position air cleaner upper section so that regulating flap in air cleaner lower section is visible.
- Connect vacuum lines to temperature regulator.
- Connect harness connector to Mass Air Flow (MAF) sensor.
- Start engine and run at idle speed.







- Check position of regulating flap after max. 20 seconds.

Temperature of temperature regulator Regulating flap position
Below 20 degree C Cold air inlet -1- closed
Above 30 degree C Warm air inlet -2- closed
Between 20 and 30 degree C Between cold and warm air inlet