A4 AHU: Vacuum Pipe Differential Interruption

Hello,

My Audi A4 (year 1997) with the AHU engine repeatedly goes into limp mode when I let it coast.

The error code in the diagnostic log indicated a "broken intake manifold pressure differential." A log file was also created.

"The VTG (Variable Turbine Geometry) isn't sticking and can be moved freely. The hoses on the solenoid valve were replaced, and then another test drive of 20 km was performed. Interestingly, the error didn't reappear. In previous test drives, the error occurred after just a few hundred meters."

LMM was updated last week.

Maybe someone would be willing to take a look at my log file.

http://www.fileuploadx.de/195735

The log does not correspond to the environmental conditions that we typically use here. Please read the technical article on log generation for more information!

Despite everything, it's quite noticeable that the boost pressure already deviates from the target by approximately 300 mbar even at low load.

Something is definitely wrong here. Please read the relevant technical articles and work through the points mentioned regarding boost pressure problems (e.g., leak in the boost pressure system, vacuum control, actuator test/basic adjustment).

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

"In my case, it was the hose between the intake manifold and the control unit."

Best regards,

An AHU does not have a VTG (Variable Turbine Geometry) but instead uses a wastegate turbocharger - Garrett T15 .

Bugs fixed.

The intercooler piping had a leak. The connecting hose to the turbocharger was torn underneath. Thank you again to everyone.