I am using PISDK.PIValues pvPIValues; to pass values to update method
I have a few questions that should help me answer you:
How are you defining pvPIValues?
What types of values do you have in there?
If the call fails, it won't throw an exception, it will only return a PIErrors collection - is this collection empty?
Would you consider using AF SDK? AF SDK is more a recommended approach. It can also update value from a PI Point. Here is the documentation https://techsupport.osisoft.com/Documentation/PI-AF-SDK/html/M_OSIsoft_AF_PI_PIPoint_UpdateValue_1.htm