Air Cleaner Housing: Testing and Inspection

Intake Air Switch-Over Valve, Checking

Via the Intake Air Switch-over valve, a flap in the air filter housing is activated.

Overview: Intake air switch-over

Electrical Test

- Disconnect connector from Intake Manifold Change-Over Valve (N156).

- Perform a resistance measurement between the valve terminals using portable multimeter (VAG1526).





Specified value: 25 to 35 ohms

If specified value is not obtained.

- Replace Intake Air Switch-over valve (N335).

If specified value is obtained.

- Check voltage supply.

Voltage Supply, Checking

- Connect voltage test lamp (VAG1527) between connector terminal 2 and engine Ground (GND) using adapter cables from connector test kit (VAG1594).





- Switch ignition on.

LED must light up.

- LED does not light up.

- Check fuse for intake air switch-over valve (relay- and fuse holder in instrument panel, right side).

If fuse is OK.

- Check wire connection from terminal 2 of connector for intake air switch-over valve via fuse to Motronic Engine Control Module (ECM) Power Supply Relay (J271) (relay carrier in E-box in plenum chamber) for open circuit/short circuit.

If voltage supply is OK, check wire connection.

Wire Connections, Checking

- Connect test box (VAG1598/31) to wiring harness of Engine Control Module (ECM).

- Check the following wire connection for open circuit/short circuit:





- Repair open circuit in wiring or short circuit if necessary.

- If wire connection is OK, replace Engine Control Module (ECM), refer to Repair Manual and generate readiness code again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.