X-Pac Preparing for Possible Jail Stint from DUI Arrest, 'I'm Ready'

... From '04 DUI

X-Pac says he may have to go back to jail ... but this time around, he's ready for it.

The WWE legend was in court in L.A. on Friday to deal with a warrant from a 2004 DUI arrest. He initially pled no contest in the case and got 3 years probation. He was also ordered to complete a drug and alcohol program.

But something went wrong and a warrant was issued for his arrest in 2005. Seems X-Pac (real name Sean Waltman) violated the terms of his deal.

The case went quiet for almost 12 years -- until X-Pac was arrested for drugs at LAX in April and ordered back to court to deal with the warrant.

So, what happens now?

"I may have to do a couple days in jail," X-Pac says ... "and if…