Repair failed

Sounds like the first repair was incorrect and it is possible that the new computer will fix this, but it would seem that the shop is responsible for the $438 repair that didn't fix your car. Your lucky, you're in California where there they have good consumer protection laws for auto repair. If this shop is unwilling to work with you on this, then contact the BAR and see what they recommend. As always, try to get them to step up and take responsibility first before taking these kinds of actions.