The DTC P0625 OBDII code means the PCM (Powertrain Control Module) has found a lower-than-expected voltage signal in the alternator field coil circuit.
The PCM monitors the continuity and voltage level of the generator field circuit whenever the vehicle is running. This coil is integral to alternator operation, as well as maintaining battery charge levels.
When a problem is detected in the generator circuit, this code will be set and the Check Engine light will turn on.