P0563: OBD-II code P0563 means the PCM has seen battery voltage climb above its maximum threshold — usually a failed voltage regulator or an overcharging alternator.

Symptoms

• Check engine light is on; other electrical modules may set lost-communication or reset codes.
• Interior and dash bulbs may burn out prematurely, and the battery may swell, vent, or leak from overcharging.
• In severe cases, sensitive electronic components (radios, control modules) can be damaged by sustained over-voltage.

Common causes

• A failed alternator voltage regulator letting charging output rise above 15 V.
• A poor alternator ground path causing the regulator to sense low and overcompensate.
• On computer-controlled charging systems, a failed BCM/PCM alternator control driver commanding excess field current.

What to do?

Measure battery voltage at idle and 2,000 RPM — should stay 13.8-14.5 V. If it exceeds 15 V, replace the alternator or its voltage regulator. Verify the alternator ground strap. On computer-controlled charging systems, scan for related PCM/BCM codes and address them first.