Intake Manifold Change-Over Checking

Intake manifold change-over, checking

This test should only be carried out if the vehicle has a performance problem or if a malfunction is stored in the DTC memory.

The intake manifold change-over between the long intake tract and the short intake tract is controlled according to engine speed.

Function, checking

- Connect Vehicle Diagnostic, Testing and Information System VAS5051 or VAG 1551 Scan Tool and select engine electronics control module by entering address word "01", Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551/ VAS 5051 Scan Tool" under "Powertrain Management" Testing and Inspection . When doing this the engine must be at idle.

Indicated on display

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -8- to select 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-, -9- and -5- to select "display group number 095" and confirm entry with -Q- button.

- Check readout in display field 4.
Specification: "IMC-V OFF"

Indicated on display

Read Measuring Value Block 95 ->
1 2 3 4

- Check specific display values for intake manifold change-over.












Increase engine RPM to the following figures to activate the intake manifold change-over function

RPM Vacuum unit
3360 Stage 1 lower unit
5280 Stage 2 upper unit







- Check whether correct vacuum unit is actuated at particular engine speed.

If the display shows "Stage 1 or 2" but the intake manifold change-over is not activated (vacuum units must drop back), test the following components:

- Check intake manifold change-over valves, Testing and Inspection