Variable Induction System: Testing and Inspection

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 and engine load.

Checking function
- Connect vehicle diagnostic, testing and information system VAS5051 or VAG1551 scan tool and select engine electronics control module by entering address word "01". When doing this the engine must be at idle. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAS5051 or VAG1551" Testing and Inspection


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 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.

Display Group 095:

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

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

Display Group 095:

- 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. Refer to Variable Induction System/Variable Induction Control Valve. Testing and Inspection