Intake Manifold Tuning (IMT) Valve, Checking

NOTES:
- Without current the tuning -N156- is closed.
- Component locations. Locations


Checking flow and for leaks
- Remove intake manifold tuning valve -N156-.
- After removing, re-connect valve -N156- to harness connector.
- Conduct output Diagnostic Test Mode (DTM) for intake manifold tuning valve -N156-. See On Board Diagnostic (OBD). Testing and Inspection
- Blow through hose to valve output DTM and make sure that -N156- opens and closes correctly.

If -N156- does not open and close:
- Replace intake manifold tuning valve -N156-.


Electrical check of intake manifold tuning valve -N156-
- Disconnect harness connector from intake manifold tuning valve.





- Connect multimeter for resistance measurement between contacts.
Specified value: 25-35 Ohms.

If the specified value is not attained:
- Replace intake manifold tuning valve.


Checking voltage supply for intake manifold tuning valve -N156-

Test requirement: Fuse for for intake manifold tuning valve OK





- Disconnect harness connector from intake manifold tuning valve.
- Connect LED test lamp VAG1527 with wires from test kit VAG1594 between terminal 1 (B+) of 2-pin connector and engine Ground.
- Crank starter.
LED must light up.

If LED does not light up:
- Check fuse for -N156-

- Check wiring from terminal 1 of 2-pin connector to fuse per wiring diagram for continuity.
Specified value: max. 1 Ohm

If wiring is OK:
- Check fuel pump relay and signal to relay. Testing and Inspection


Checking signal for intake manifold tuning valve -N156-
- Connect LED test lamp VAG1527 with wires from test kit VAG1594 between terminals of 2-pin connector for -N156-.
- Conduct output Diagnostic Test Mode (DTM) for intake manifold tuning valve -N156-. See On Board Diagnostic (OBD). Testing and Inspection
When the intake manifold tuning valve is activated the LED must flash.

If LED does not flash or stays on continuously:
- Connect VAG1598/22 test box to ECM harness connector. Testing and Inspection

If LED does not flash:
- Check wiring from terminal 2 of 2-pin connector to terminal 64 of test box for continuity and short circuit to B+ per wiring diagram.

If LED stays on continuously:





- Check wiring from terminal 2 of 2-pin connector to terminal 64 of test box for ground per wiring diagram.

If wiring is OK:
- Replace Motronic ECM -J220-.
- Carry out adaptation of throttle valve control module to ECM. Testing and Inspection
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code. See On Board Diagnostic (OBD). Testing and Inspection