Intake Manifold Tuning (IMT) Valve, Checking

Intake Manifold Tuning (IMT) valve, checking


NOTE:
- Without current the intake manifold tuning valve -N156- is closed.


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-.Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" Testing and Inspection
- Blow through hose to valve during 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 requirements
- Fuse for for intake manifold tuning valve OK







- Disconnect harness connector from intake manifold tuning valve.
- Connect LED test lamp VAG 1527 with wires from test kit VAG 1594 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 VAG 1527 with wires from test kit VAG 1594 between terminals of 2-pin connector for -N156-.
- Conduct output Diagnostic Test Mode (DTM) for intake manifold tuning valve -N156-.Refer to "Scan Tool Testing/Output Diagnostic Test Mode (DTM) (Function 03)" 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 VAG 1598/22 test box to ECM harness connector.Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1598/22 Test Box" 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.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Checking Readiness Code" Testing and Inspection
Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code Testing and Inspection