on my 2016 cls550 these are the codes and not sure if anyone here had similar experience. thanks for your time

Have you erased codes to see if they return. If they return, may be auxiliary battery - MB part 0009829608 (should also pull compatible aftermarket).

I did try easing code but keeps coming back. do I try to charge auxiliary Battery or just replace it?

Given your situation, depending on water damage replacement may be needed.

https://mbworld.org/forums/cls-coupe...ease-help.html
https://mbworld.org/forums/cls-coupe...sue-codes.html

so I did replace battery and most problem got resolved but one. can someone assist?? error code is 9EA953. thank you

You need to check for leaks to bladders (700 in diagram) and/or valve lines (750). See attachments to gain access.