Ladedruck bei 2600mbar ohne dass der Motor läuft | Posts 16+

"Today, I intermittently received readings for the actual boost pressure in measurement block 11, but only while the engine was warming up. During this warm-up phase, the actual boost pressure remained below 3 bar at all times. The target boost pressure was always lower than the actual value."

Once the engine was warm, I couldn't clear the error code anymore.

After that, the actual and target values were permanently fixed and did not change.

"I would start by disconnecting the boost pressure sensor. If the displayed actual boost pressure then shows the ambient pressure, the boost pressure sensor is defective."
If the actual charging pressure displayed is still much too high, you have a problem with the wiring or the engine control unit itself.

Best regards, Rainer.

Should I disconnect the plug or remove the boost pressure sensor from the intake manifold? Wouldn't that then display the ambient air pressure, which would be correct?

I replaced the boost pressure sensor with one from a different vehicle. The old sensor works perfectly fine in the other vehicle.

After resetting the engine control unit and allowing the engine to cool down, I retested the values in a cold state. In VCDS, I see the target and actual values as long as the engine is warm. After that, the error code appears and cannot be cleared. The target and actual values then remain unchanged. I suspect this is a consequence of the engine's limp-home mode.

The throttle valve was removed and cleaned, as well as the intake manifold. The throttle valve only had an opening of approximately 15mm in the center. The swirl flaps in the intake manifold could also hardly be turned.

Which pins of the MSG connect to the boost pressure sensor?

The required voltage is present at the sensor terminal. The turbocharger boost pressure temperature (G42) is also being displayed correctly.

Could it be due to the VTG (Variable Turbine Geometry) adjustment if it gets stuck in a certain position, causing the turbocharger to constantly deliver excessive pressure? Or can I rule this out?

Quote:

Unplug the connector

.
The engine control unit must then display the ambient pressure as a substitute value (using a sensor built into the control unit).

Best regards, Rainer.

When the boost pressure sensor is disconnected, a value of 2202 mbar is displayed for both the target and actual values.

The error was due to a broken cable for the G31 sensor. The cable was broken directly at the connector, which is why it sometimes worked and sometimes didn't.

The pins for the sensor on the MSG (Motor Steuergerät - Engine Control Unit) in the BMN 2.0 TDI 170 PS Touran are...

T94 connector.

G42.

Pin 76 and Pin 38.

G31

Pin 62 and Pin 78.

Thank you for your feedback!