Purge Flow Low
Had small evap leak code before, found the purge solenoid to be faulty, changed it out & also installed new gas cap, as soon as I test drive within 3miles pending code sets for P0497 purge flow low. ohmed out new and old solenoids, old 1 was at 25kOhms & new one was at 30k ohms.
I recommend you run through the complete diagnostic flow chart for P0497 to narrow down what it is (how did you prove the solenoid was faulty?). Also do not assume a new part means it is good. I have had many bad fuel caps and had to go with OE. You started with a small evap leak code (P0442?) and now you have a low purge flow code? Is the purge solenoid OE?
Toss the Vemo, get O.E or better quality purge solenoid. I have dealt with a lot of Vemo products being junk out the box. Just my 2 cents.
No way a purge solenoid should have 30k ohms. That's literally an open circuit. Have you check to see if it even opens when commanded?? Sounds like it needs OE.
I agree with others about going with OE. And since the low flow code came after replacement you just can't trust it. Anytime I need to replace a purge or vent valve, I always go with OE. Learned the hard way just like you just did.