Toyota Motor Corp.'s goal of a decision this month to keep or close a California joint venture discarded by General Motors Corp. may be hindered by bankruptcy court.

Toyota aims to decide by the end of July whether to become sole operator of New United Motor Manufacturing Inc., or NUMMI, after bankrupt GM quit the venture on June 29, a source said Wednesday.

GM's discarded factory sites, real estate and other unwanted assets are to be auctioned for repayments to creditors, including NUMMI itself, which claims to be owed $722,662.08 by the Detroit-based carmaker, according to a filing. Toyota created a team to assess NUMMI's value and complete a review prior to any talks on buying the stake, said the source, who asked not to be identified as the plan isn't public.