Intake Manifold Tuning Valve, Checking

Intake Manifold Tuning Valve, Checking

Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.

Test requirements
- Fuse SB7 OK.
- The Motronic Engine Control Module (ECM) Power Supply Relay J271 OK.
- The parking brake engaged.
- The battery voltage at least 12.5 V.
- The selector lever of automatic transmission in position "P" or "N".
- All electrical consumers switched off (radiator fan must NOT run during test).
- A/C switched off.
- The fuel tank at least 1/ 4 filled.
- The ignition switched off.

Test procedure
- Perform a preliminary check to verify the customers complaint. General Diagnosis

Start diagnosis







- Disconnect the Intake Manifold Runner Control (IMRC) Valve N316 electrical harness connector - arrow -.

Checking internal resistance







- Using a Multimeter, check the Intake Manifold Tuning (IMT) Valve N156 terminals 1 to 2 for resistance.

Specified value: 450 to 1000 Ohms.

If the specified value was not obtained:
- Replace the Intake Manifold Tuning (IMT) Valve N156.

If the specified value was obtained:

Checking voltage
Crank the engine.







- Using a Multimeter, check the Intake Manifold Tuning (IMT) Valve N156 electrical harness connector terminal 1 to ground (GND) for voltage.

Specified value: battery voltage.
- Switch the ignition off.

If the specified value was not obtained:
- Check the wiring from the Intake Manifold Tuning (IMT) Valve N156 electrical harness connector terminal 1 to the Motronic Engine Control Module (ECM) Power Supply Relay J271 socket 2/87 for a short circuit to Ground (GND), or an open circuit.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box VAG1598/31.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J220.
- Using a multimeter, check the Intake Manifold Tuning (IMT) Valve N156 electrical harness connector terminal 2 to the Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 121 for resistance.

Intake Manifold Tuning (IMT) Motronic Engine Control Module (ECM) J220
Valve N156 electrical harness electrical harness connector terminal
connector terminal or test box socket
2 121

Specified value: 1.5 Ohms Max.

If the specification was not obtained:
- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:
- Erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
- Perform a road test to verify repair.

If the DTC does not return:
Repair complete, Generate readiness code. Readiness Code
- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J220.
- Assembly is performed in the reverse of the removal.

Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.

End of diagnosis