VW TDI PD BLS Exhaust Cooler with DPF and Vacuum Control

Hello,

VW Golf 2009 1.9 PD DPF BLS 230.000km
It's only about the exhaust gas cooler, not the AGR!

What effects can a faulty pressure canister / stuck shaft or flap of the exhaust gas cooler (not the AGR) have on the engine during operation?
There are no error entries.

Please, as always, only provide technical answers.
Regards

Depending on the operating conditions, the necessary exhaust gas recirculation rate may not be achieved, so that the Readiness Code (System Self-Test) cannot be successfully completed in the long term.

Furthermore, the engine will warm up more slowly without AGR cooling.