ALH Intake Manifold Flap Problem & Fix

Hi,

Since this morning, I've been having a small problem with the intake manifold flap on my ALH engine.

I tried searching, but unfortunately I couldn't find anything comparable to my problem.

He does the following, but not always.
Jeden 3. oder 4. Engine start!

The engine is idling normally, but when the throttle is opened (while stationary), the intake manifold flap closes at approximately 1300 RPM. This creates a vacuum in the intake manifold, reaching up to -0.85 bar (as indicated on the boost gauge!).

During operation, the boost pressure increases to a maximum of 1.1 bar, but it should ideally be around 1.5 bar.

If I disconnect the connector for the throttle valve sensor (N239), the engine runs without any problems and the boost pressure gauge also shows the correct target air pressure.

Error memory is empty.

There are approximately 5 to 5.2 volts at the connector.

If he tries to close the throttle valve during acceleration again, it briefly shows a voltage of up to 13.8 volts (battery voltage).

The wiring has been checked, and no cable breaks or other connection issues were found within the circuit (either on the positive or ground side).



Could there possibly be a problem with the control unit ?

But why doesn't it always happen?



By the way, my EGR valve is defective (and deactivated).


Perhaps someone who has encountered this problem before can help me.


Best regards,
Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

What do you mean by "throttle valve"? Are you referring to the shut-off valve located before the EGR valve? On the ALH engine, it only closes briefly when the engine is off, triggered by the engine control unit (ECU).
The hinge could be faulty or loose, causing the door to no longer stay properly in its horizontal position.

If he applies voltage there, the MSG will get a jolt.

Because the shut-off valve, or its solenoid valve, is designed to be activated only when shutting down the system.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

I have the same suspicion.

I'll probably have someone adjust a different engine control unit (immobilizer) that I have lying around sometime soon.

Hopefully, I can salvage the modified software!

Okay, the control unit is definitely defective!

This morning I went to the "Friendly" service center, but unfortunately they were unable to adjust the new (different) control unit. The online connection kept dropping out repeatedly.

Reinstalled the old control unit, read and cleared the error memory.
Unfortunately, two errors cannot be deleted anymore!

- Preheating indicator light, short circuit to positive terminal, static.

- Charge pressure control valve, short circuit to positive voltage, static.

Just for fun, I reinstalled the new control unit and checked the error memory, and it was empty except for "Engine control unit locked" (immobilizer).

Arrived back home slowly with the old control unit, checked the wiring again, everything was fine, installed a different solenoid valve, but still the same problem.

After checking again with the diagnostic tool as described above, the error codes cannot be cleared with the old control unit. With the new control unit, only the engine control unit is not authorized to start the vehicle.

I'll check with the dealership again next week and hope that it works out this time.

I will report back later.