Subaru Repair: subaru 2003 impreza outback, brake noise, brake pads

Question
Just had 30k done at dealer and they had me put new front brake pads (total cost $850).  Now when I slow down (brake) to a stop I can hear squealing.  What could it be?

2nd question.  Yesterday when driving on the freeway when I went over 75mph check engine light started flashing.  It went away when I went down under 65 (which I stayed under 60 since then).  Do you think it could be related to the 30k service?  I never had that happen before.

Answer
Tim,

There are so many possible problems in regards to either question.

The brake noise could be one of many issues, such as grease on the surface of the pad or rotor.

Why not just take it back to the dealer and have them check there work?