P0171 and P0174 are system running lean conditions. It could be vacuum leaks or a host of sourves and does not indicate what component is faulty. It could also be due to low fuel fuel pressure or caused by the knock sensor.
P0320 and P0325 - Knock sensors fault, left and right bank respectively.
Knock sensors failure are common for such vehicles.
All the 4 codes have no relations to the transmission not shifting to O/D which can be due to a fault with the O/D solenoid stiicking.
Sometimes problems are coincidental and you should not keep thinking it is related to the alternator replacement. Test the O/D solenoid first.
Friday, December 28th, 2012 AT 1:03 PM