Variable Induction System: Testing and Inspection

Intake Manifold Change-Over, Checking

The first stage of the intake manifold change-over is not available on any S8 vehicle

This test should only be performed if there is a performance deficiency of if a malfunction is stored.

The intake manifold change-over from the long intake path to the short path is RPM dependant.

Checking function
- Connect VAS5051 tester or VAG1551 scan tool and select the control module for engine electronics via "address word" 01. Engine must run at idle for this. 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 "Read measuring value block" function 08. Press - Q- button to confirm input.

Indicated on display:


Read measuring value block
Enter display group number XXX


- Press buttons -0-, -9- and -5- to select "Display group number 95" and press -Q- button to confirm input.

Indicated on display:


Read measuring value block 95 ->
1 2 3 4

Display Group 095:

- Check specified value for intake manifold change-over.







Specified value in display field 4: "SU-V OFF" vacuum diaphragms pulled in

Increase engine speed to approx. 5400 RPM to initiate intake manifold change-over.

Display Group 095:

- Check whether the vacuum diaphragms are being activated.







If "SU-V ON" is indicated, but the intake manifold change-over is not being initiated (vacuum diaphragms must release), check the following components.
- Check solenoid valves for intake manifold change-over. Refer to "Intake Manifold Change-Over Valve -N156-, Checking" under "Powertrain Management", Testing and Inspection