My daughter father and I went to court about a year ago but we never finalized the paperwork in the state of California. As of July 2012 was the last time my daughter went for her weekend visit with her father. He came to see her once in September and today 10/24/12 he called came by and said he wanted to come by... when he arrived he told my daughter he just wanted to say bye... and started to walk away... I asked if he was going somewhere and he said yes that he was going out of town and when I asked when he was coming back he said he didn't know but in a long time! Didn't leave word of where he was going or any info. Is this considered abandonment? Can I file against him? I want to travel to mexico my home country how can I do that with out a consent letter from him? I already have her passport and he has already let me travel with her to mexico. Will a judge grant me full legal custody since I already technically have full custody.

You may use abandoment to file in court for a change in custody, You can file for permission in court to travel, if after you ask him he says no, so you can try to use this in court.

You can't "file for abandonment", but you can use abandonment as grounds for getting sole legal custody. However, to use abandonment as grounds, requires more time. He just walked out today and you have no proof that he won't be back tomorrow.

I would make attempts to contact him to ask for a standing letter giving you permission to travel with your child. If you can't contact him for 6 months, then you can go to court for sole legal custody.