when i turned the car off tonight but leaving the key in the 2nd position to keep the radio on, i got a "brake lining wear" message.. but the rears were replaced not so long ago, and the fronts looked ok on inspection?

funny thing is, i restarted the car and i have not seen the msg again. is the brake wear warning supposed to go off and never come back?

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Current cars:
2001 MB E55 AMG
2003 Honda S2000
2000 Honda CRV

Gone but not forgotten:
2004 BMW 325i 5sp sport
1999 BMW 540i sport
1997 MB E420
1995 BMW M3 coupe