code 41 92 new yorker fith ave.

i'm getting a code 41 on my 1992 new yorker fith ave. in the book it says low current to asd relay below 11.75 volts? also had autozone tell me bad field current, but alternator is good??
and help would be great?

ok here's the choices i came to:
 
new alternator? $130.00
New ECM $200.00
 
I wonder how much chrysler would charge to determine it for me?? $$$

chrysler wants $85 to tell me whats wrong,
 
I just bought the alternator, installed and no more cutting out, no more code 41.