41 An open or shorted condition detected in the generator field control circuit
I can't find any reference to code 45. Based on the need to work with the battery, my guess is the previous owner had a charging problem, didn't know what to do about it, and you still have the same problem. By "brain", do you mean the Engine Computer or are you referring to something else? What led you to that? As for "what else can you do", what are you trying to fix? What is the symptom or problem?
For code 41, chances are the alternator isn't charging the battery. I don't know which engine you have, but if it uses the little silver Nippendenso alternator, worn brushes are pretty common and easy to replace. You would find that by measuring the voltages on the two smaller wires bolted to the back of the alternator. One must have full battery voltage. The other must have less but not 0 volts. If you find 0 volts on the second wire, the brushes are open. If you find exactly the same battery voltage on both wires, there is a break in the wire between the alternator and the voltage regulator in the Engine Computer. The regulator in the computer gives very little trouble.
Saturday, February 9th, 2013 AT 11:10 AM