Intake Manifold Change-Over Valve -N156-, Checking

Intake Manifold Change-over Valve -N156-, Checking







Special tools and equipment
- VAG1526 A
- VAG1527 B
- VAG1594 A
- VAG1598/31
- VAS5051 with VAS5051/1

Test sequence







- Remove front engine cover (arrows).







- Disconnect connectors to intake manifold change-over valve -N156- -pos. -1-.

Checking internal resistance







- Connect multimeter to injector to measure resistance.

Specified value: 25 to 35 Ohms

If specified value is not obtained:
- Replace intake manifold change-over valve -N156-.

If specified value is obtained:

Checking power supply
Test requirements
- Fuse for intake manifold change-over valve OK
- Fuel pump relay OK; checking.

NOTE: Power supply of the intake manifold change-over valve is via the fuel pump relay.







- Connect voltage tester VAG1527 B as follows:

Connector Measure to
terminal
1 Engine ground

- Operate starter briefly.
- LED should illuminate.

If the LED does not illuminate:
- Check wiring from terminal 1 on connector via fuse to fuel pump relay for an open circuit.
- Repair open circuit if necessary.

If LED lights up:

Checking actuation







- Connect voltage tester VAG1527 B between terminals 1 and 2.
- Initiate final control diagnosis and activate intake manifold change-over valve.
- LED should flash.

If the LED lamp does not flash or if it illuminates continuously:
- Connect test box VAG1598/31 to wiring harness for engine control module; engine control module must not be connected.
- Check for open circuit and short to positive or Ground in following wiring connections:

Connector Test box VAG1598/31
terminal Socket
2 48

- Repair any open/short circuit as necessary.

If no wiring malfunction is detected:
- Replace engine control module.