A stored code P0622 means that the powertrain control module (PCM) has detected a malfunction with the generator field coil control circuit. ... The PCM monitors the continuity and voltage level of the generator field control circuit whenever the engine is running. If you look at your alternator you'll see the field coil windings inside the case through the cooling vents.
OBD II fault code P1602 is caused by the Engine control module (ECM) detecting that the supply voltage is low from the battery”, or sometimes as “Power Supply (B+) Terminal 30 Low Voltage”, and is set when the PCM (Powertrain Control Module) detects that the battery current being supplied to the PCM when the ignition is switched off, is below a minimum allowable threshold.
A code P1391 indicates that your camshaft position sensor is sending erratic signals to the Powertrain Control Module (PCM). Given your other electrical issues I suspect that your crank position sensor harness or connector is corroded, dirty or possibly shorting out.
It may be causing a parasitic draw on your battery and it also appears that your alternator may not be charging your battery sufficiently.
It can all be fixed as a good tech will find any parasitic draw, fix that then move on to the other two issues.