With Manufacturer's Scan Tool

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

Special tools and equipment





- Hand vacuum pump VAG 1390
- Test box VAG 1598/31
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594
- Wiring diagram

Check conditions






- The fuses must be OK.
- The battery voltage must be at least 11.5 V.

Checking function
- Start engine and run at idling speed.
- Switch off ignition.
- Observe position of lever on change-over valve for intake manifold flap -N239- (2nd technician required).
- The intake manifold flap must, after switching off ignition, close and after approx. 3 seconds open again.

If change-over does not occur, the following checks must be carried out.
- Check intake manifold flap change-over mechanics for freedom of movement. To do this operate rods by hand.






- Pull vacuum hose off vacuum unit -1-.
- Connect hand vacuum pump VAG 1390 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 fault is found in the mechanical components:
- Check intake manifold flap change-over valve.

Test sequence
- Disconnect connector on intake manifold flap change-over valve.






- Measure resistance between change-over valve terminals.
Specification: 25 to 45 Ohm

If the specification is not obtained:
- Replace Change-over Valve for intake Manifold Flap -N239-.
- Check DTC memory and, if necessary, repair any malfunctions and then erase. With Manufacturer's Scan Tool
- Read readiness code. If the DTC memory has been erased or the Diesel Direct Fuel Injection Engine Control Module - J248- was disconnected from permanent battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

If the specification is obtained:






- Set multimeter to measure voltage and connect to terminal 1 and 2 of disconnected connector from Change-over Valve for intake Manifold Flap -N239-.
- Start engine and run at idling speed.
Specification: at least 4.5 V
- Switch off ignition. Value for voltage must drop to 0.0 V after about 3 seconds.

If the voltage values do not change as described:
- Remove wiper arms and plenum cover.






- Connect test box VAG 1598/31 to control unit wiring harness.






- Check wiring between test box and connector for open circuit using wiring diagram.
Terminal 1 + socket 1 and 2
Terminal 2 + socket 81
Wire resistance: max. 1.5 Ohm
- Check wires for short to one another, to vehicle Ground and to battery positive (B+).
Specification: Infinite Ohm

If no wiring malfunction is detected:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.