2008 Chrysler Aspen What is code bu5

Did you get this code from a scanner or is it displayed on the instrument panel?

"B" codes are body codes and are generally 4 digits, (Bxxxx).

B2925 for example is "Audio button stuck".

B1E65 is "right mirror select switch stuck".

If displayed on instrument panel it may be a maint. Code or abbreviation for something else.
Check owners manual for info, and BU5 may also be BUS.

There are no 3 digit "B" codes for a Chrysler.