12 is a parity error. Check placement of your BP magnets. you may want to swap PMI modules with another car and see if problem follows. Also look at your guides. They are critical. Rule of thumb--when front to back play exceeds 1 thickness of the selector tape, you should order and replace at next service visit. In a pinch, you can flip all left sides with the right sides and use the unused guides. The power supply is a 15vdc. 15.2 or 15.5 would be good. There is also 24V supplied to the selector for the outputs. You may have a line drop in voltage. I usually run my 24 volt supplies up as high as 26vdc, at the power supply, if possible. But this is your call.