Intake Manifold Tuning (IMT) Valve, Checking

Intake Manifold Tuning (IMT) Valve, Checking

Intake Manifold Tuning (IMT) valve, electrical testing
- Switch ignition on.

Initiate output Diagnostic Test Mode (DTM) and check actuation of intake manifold change-over valve -N156-. Output Diagnostic Test Mode (DTM) (Function 03)


Output Diagnostic Test Mode ->
Intake manifold change-over valve -N156


The valve should click (confirm by sound and touch). After one minute, the output DTM will be interrupted.

If valve does not click:
- Switch ignition off.
- Disconnect harness connector from IMT valve.







- Connect multimeter US 1119 (Fluke 83 or equivalent) and measure resistance across IMT valve terminals.
Specified value: 25-35 ohms

If resistance is not OK:
- Replace intake manifold IMT valve.

If resistance is OK:







- Connect VAG1527B LED voltage tester between harness connector terminal 1 and Ground, using adapter cables from VAG1594 connector test kit.
- Switch ignition on.
LED must light up.

If LED does not light up:
- Check fuse for intake manifold IMT valve in electronics box (E-box) in plenum.

If fuse is OK:
- Check wiring for open or short circuit between IMT valve harness connector terminal 1 and fuse in E-box.

If wiring (voltage supply) is OK:
- Connect VAG1598/19 test box to ECM harness connector. Connecting VAG 1598/19 Test Box






- Check wiring for open or short circuit between IMT valve harness connector terminal 2 and ECM/test box socket A5.

If wiring is OK:
- Replace ECM and generate new readiness code. Readiness Code, Generating
- Check intake manifold IMT valve function. Refer to "Intake Manifold Tuning (IMT) Valve/Function, Checking" Testing and Inspection