A misspelling for the French word "Ça va" which means "How are you?" "How goes it?"
People would often reply "Ça va bien, Merci. Et toi?"
Which would mean "It goes very good, thank you. And you?"
A person who replies with "Ça va" means it's just going good.
Bonjour, Ça va?
Bonjour. Ça va bien, et toi?
Ça va! :D
Only a n00b would use ca va.