Intake Manifold Change-Over, Checking Function

Intake Manifold Change-Over, Checking Function

• The following test should only be performed if there is a performance deficiency.

- Increase engine speed to noticeably above 5400 RPM.

Specified value: Vacuum diaphragm for the intake manifold changeover must activate.

If vacuum diaphragm does not activate:

- Check vacuum lines for proper connection, sealing and continuity, overview.

- Check whether the change-over mechanism moves easily. (Operate change-over linkage by hand as a test).

- Check-valve (black/white) leaky, clogged or incorrectly installed.

- Intake Manifold Change-Over Valve faulty (does not switch through or clogged).

- Check Intake Manifold Change-Over Valve (N156) => [ Intake Manifold Change-Over Valve, Checking ].

- Check vacuum system for proper seal => [ Vacuum System, Checking for Leaks ].

Overview: Intake manifold change-over





1 Intake Manifold Change-Over Valve (N156)

• Activation for both vacuum diaphragms

2 Vacuum diaphragms for intake manifold change-over

3 Intake Air Switch-over valve (N335)

• Activation for flap in air filter

a - T-connector for vacuum supply from intake manifold change-over valve

b - Vacuum supply from intake manifold

c - Vacuum line to low pressure reservoir (vacuum reservoir)

d - T-connector for vacuum supply from Intake Air Switch-over valve (N335) and low pressure reservoir

e - T-connector for vacuum supply from Intake Manifold Change-Over Valve (N156)

f - Vacuum line to flap in air filter