They'll send you a letter within a couple weeks if they changed something on your return. You ca try to call before that but you probably won't get any information until you have the letter. Look at your CA return to make sure of your refund amount and that you're not adding together the federal and the state.
Sounds like that was your refund. If the state adjusted your return they will mail you a letter. Maybe you can find the difference on your 540 return. Check the payment lines and see if the withholding is right and if it shows any payments or estimates you didn't make.
They'll send you a letter within a couple weeks if they changed something on your return. You ca try to call before that but you probably won't get any information until you have the letter. Look at your CA return to make sure of your refund amount and that you're not adding together the federal and the state.