20 Most Recent Pioneer DEH-P6800MP CD Player Questions & Answers

hi,

• From page 14 of the owner's manual, the error code AO indicates an "Electrical or Mechanical cause"; they recommend turning the ignition off and then back on, and then toggling from CD to radio and back to CD again.
  
  If you're still getting the error code, then you can try to check for loose connections yourself (or perhaps a jammed disc?), but you'll probably have to take it to a certified Pioneer Service Center or the dealer where you purchased the unit.
• good luck!
  

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No reason being the perminent live that keeps the memory for the radio is obviously still feeding the CD side with ignition off.