P CODES (POWERTRAIN) P0400 - P0499 P0461 Questions

Car Is Giving Me Code P0461, But A Mechanic Said It Could Be My Alternator.

I Am Getting Codes P0460 And P0461 And Cel Is Lit. When Cleared, These Codes Return A Short Time Later, Generally Within 30 - 100 Miles...

I Am Very Familiar With Bmws But Never Seen This Code Before, 93,000 With No Issues All Of A Sudden Two Miles Away From Home And I Get...