TDI Exhaust Cooler: VW PD BLS DPF with Vacuum Valve

Hello,

VW Golf 2009, 1.9 PD DPF, engine code BLS, 230,000 km.
It's only about the exhaust gas cooler, not the EGR system!

What effects can a faulty pressure sensor/stuck shaft and/or valve in the exhaust gas recirculation cooler (not the EGR valve) have on the engine during operation?
There are no error entries.

Sure, I will provide only the translation.

'Übersetze folgenden Text von Deutsch nach Englisch. Gib NUR die Übersetzung aus, keine Erklärungen.'

'Please translate the following text from German to English. Provide ONLY the translation, no explanations.'
Best regards,

Depending on the operating conditions, the required exhaust gas recirculation rate may not be achieved, which could prevent the Readiness Code (System Self-Test) from completing successfully in the long term.

Furthermore, the engine warms up more slowly without the EGR cooling system.