With Manufacturer's Scan Tool

Change-Over Valve For Intake Manifold Flap, Checking

Special tools and equipment






- VAG 1390 Hand vacuum pump
- Test box VAG 1598/22 (through my 1999)
- Test box VAG 1598/31 (from my 2000)
- Digital multimeter US1119 (Fluke 83 or equivalent)
- Adapter set VAG 1594
- Wiring diagram

Requirements






- Fuse 34 must be OK
- The battery voltage must be at least 11.5 V

Checking function

- Start engine and run at idling speed.
- Switch ignition off.
- Observe position of lever on change-over valve for intake manifold flap (2nd technician required).
- The intake manifold flap must (after ignition is switched off) close and after approx. 3 seconds open again

If change-over does not occur, perform the following checks:






- Pull vacuum hose off vacuum unit -1-.
- Connect hand vacuum pump VAG 1390 or equivalent to vacuum unit.
- Operate hand vacuum pump and check intake manifold flap change-over mechanism for ease of movement and operation.
- Check vacuum lines for correct connection.

If no malfunction is found in the mechanical components:
- Check change-over valve for intake manifold flap.

Test sequence

- Disconnect change-over valve for intake manifold flap connector.






- Measure resistance between change-over valve terminals.
Specification: 25.0 - 45.0 ohms

If the specification is not obtained:
- Replace Change-over Valve for intake Manifold Flap -N239-, refer to item 10 Service and Repair
- Check DTC memory and, if necessary, repair any malfunctions and then erase, refer to "Diagnostic Trouble Code (DTC) Memory, Checking and Erasing" Testing and Inspection
- Read readiness code.

If the DTC memory has been erased or the engine control module was disconnected from permanent battery positive (B+), the readiness code must be generated again.

If the specification is obtained:






- Measure voltage supply for changeover valve between the terminals of the connector.
- Start engine and run at idling speed.
Specification: 5.0 - 6.0 V

- Switch ignition off.
Voltage value must increase to 11.0 - 15.0 Volts (battery voltage) and after approx. 3 seconds fall to 0.0 Volts

If the voltage values do not change as described:

- Remove wiper arms and plenum cover.






- Connect test box VAG 1598/22 (through my 1999) or VAG 1598/31 (from my 2000) to control module wiring harness.






- Check wiring between test box and connector for open circuit according to wiring diagram.






Wire resistance: max. 1.5 ohms

- Check wires for short to one another, to vehicle Ground and to battery positive (B+).
Specification: Infinity ohms

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