Section 3--408. Consideration

Want  or  failure  of consideration is a defense as against any person
  not having the rights of a holder in due course (Section 3--305), except
  that no consideration is  necessary  for  an  instrument  or  obligation
  thereon  given in payment of or as security for an antecedent obligation
  of any kind. Nothing in this section shall  be  taken  to  displace  any
  statute   outside   this  Act  under  which  a  promise  is  enforceable
  notwithstanding lack or failure of  consideration.  Partial  failure  of
  consideration is a defense pro tanto whether or not the failure is in an
  ascertained or liquidated amount.