With Manufacturer's Scan Tool

Change-Over Valve For Intake Manifold Flap -N239-, Checking

Special tools

- VAG 1390 Hand vacuum pump
- VAG 1598/22 Test Box (MY 1999)
- VAG 1598/31 Test Box (from MY 2000)
- Fluke 83 multimeter
- VW 1594 Adapter kit
- Wiring diagram

Function, checking
- Start engine and let idle.
- Switch OFF ignition.
- Observe position of lever on intake manifold change-over flap (using 2nd technician)
- Intake manifold change-over flap must (after switching OFF ignition) close back and after approx. 3 seconds re-open.

If change-over does not occur, perform following checks
- Check intake manifold change-over flap mechanics for freedom of movement by manually operating the rods by hand.
- Check vacuum function of positioning actuator using VAG 1390 hand vacuum pump.
- Check vacuum lines for correct connection.

If mechanical components OK
- Check Intake Manifold Change-over Valve -N239-.

Test sequence
- Disconnect -N239- harness connector.

- Measure resistance between -N239- terminals.
Specification: 25 to 45 Ohms

If specification not obtained
- Replace Intake Manifold Change-over Valve -N239-.

If specification obtained
- Switch Fluke 83 multimeter to 20 Volt range.

- Connect multimeter between terminals 1 and 2 of ECM connector using jumper wires from VW 1594 Adapter kit.
- Start engine and let idle.
- Specification: between 5 and 6 Volts
- Switch OFF ignition.
- Voltage value must rise to 11 to 15 Volts (battery Voltage) and after approx. 3 seconds fall to 0 Volts.

If Voltage values do not change as described

- Connect VAG 1598/22 (or 1598/31) Test Box to ECM wiring harness.

- Check wiring for open circuit between Test Box and connector using Wiring diagram.

Up to MY 1999
- Terminal 1 + socket 3
- Terminal 2 + sockets 2 and 28

From MY 2000
- Terminal 1 + socket 81
- Terminal 2 + sockets 1 and 2
- Wire resistance: 1.5 Ohms maximum
- Check wires for shorting to: one another, Ground and Battery +.
Specification: Infinity Ohms

If wiring OK
- Replace Engine Control Module - J248-.