VAGCOM Troubleshooting Guide: How to Fix Issues

Hello everyone.

TDIs can also exhibit performance issues even when there are no error codes stored, because error entries are only triggered by "very incorrect" measured values, and these values must persist for a certain period of time (except for the relatively strict monitoring of the VP37 injection pump control unit).
Several similar posts indicate that this kind of thing happens relatively often.

VAGCOM, with its ability to "look inside the engine," is generally quite suitable for identifying the causes of problems, but due to its numerous options, it tends to be confusing (apparently even for some brand workshops ).

Therefore, I once tried to create a guide for systematic checks when diagnosing power loss issues without any error codes being stored. Unfortunately, it's mainly focused on VP37 TDI engines, as I don't have enough information and practical experience for VP44 and PD engines.

Rainer has published the text as a new article online.

Since many people know more than one, I kindly ask you to occasionally read through the text and post suggestions for improvements and additions (especially for troubleshooting and potential specific features of engines with the VP 44), so that everything can be compiled into a comprehensive and practical guide.

Thanks to Ulf, it's really great to see how some people here are putting in a lot of effort for the benefit of everyone.

best regards,
arne