This might not make sense but I believe in trying everything before ordering new stuff

I had a check/clean cell warning one time and like you even though it didn't look really dirty I cleaned the cell as directed but the message came back shortly after putting everthing back together. After playing a bit (cleaning contacts, etc) I finally thought about checking the inline filter screen and even though I didn't have a flow warning it was pretty dirty so I cleaned it out and Viola!! the message went away.

I didn't get as far as checking voltage/current readings and have no idea why the system was reporting cell warning rather than flow warning (which it does when the filter screen gets really dirty and the pump is on low). Maybe it triggered both alarms and the cell warning has a higher priority so it was the one being displayed and would not clear until the flow was sufficient to check the cell. Perhaps Poolsean can explain or tell me I'm crazy or it could be one of those pool mysteries that is never solved but it worked for me so maybe it will work for you!! Good luck.