P0563 means System Voltage High. The engine computer has seen supply voltage above its normal range, which usually means the charging system is overcharging. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0563 means
Modern vehicles have many control modules that share information over a network, usually called the CAN bus. Codes starting with U mean a module has stopped hearing another one, and voltage and processor codes mean a module is not getting clean power or has an internal fault. Low battery voltage, poor grounds, blown fuses and damaged wiring cause many of these codes, so test the battery and charging system first.
P0563 symptoms
- Bright or flickering lights
- Battery warning light
- Battery smelling of sulfur or swelling
- Bulbs and modules failing
Common causes of P0563
- Failed voltage regulator in the alternator
- Faulty charging system control or sensing wire
- Poor battery ground affecting voltage sensing
How to diagnose P0563
- Measure charging voltage at the battery; above about 15 volts is too high on most vehicles
- Check the alternator connector and sensing circuit
- Check battery and engine grounds
Can you drive with P0563?
Briefly only; overcharging damages the battery and electronics.
P0563 tips
Overcharging slowly cooks the battery and can damage modules and bulbs. If charging voltage is high, check the battery ground and the alternator sensing circuit before replacing the alternator, because a poor ground can make the regulator overcharge.
Will P0563 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0563 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0562 | System Voltage Low |
| P0601 | Internal Control Module Memory Check Sum Error |
| P0606 | Control Module Processor |
Guides that help
When it is more than a sensor
Voltage and network codes come from wiring, the battery, the charging system or a module, not from engine or transmission wear. If a lost-communication code has left the transmission in limp mode, rule out the module and wiring before deciding the unit has failed, and see our transmissions only if testing confirms internal damage.
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