P0563Generic code

P0563 Code: System Voltage High

The P0563 code means system voltage is too high, usually because of a faulty alternator voltage regulator. Overvoltage can damage the battery and the electronics.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$100 to $700
Difficulty
Medium
System
Computer and Outputs
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0563 code means

The computer constantly measures the supply voltage it receives. With the engine running it should be between about 13.5 and 14.7 V (alternator charging). With the engine off it should be between 12.4 and 12.7 V if the battery is in good condition.

The P0563 code means the voltage is above the maximum, often more than 15.5 to 16 V. The typical cause is a failed voltage regulator that lets the alternator charge without a limit. It can also come from a jump start with the cables connected wrong or from a battery charger that is too powerful.

Sustained overvoltage makes the battery boil and can damage bulbs and electronic modules.

On alternators managed by the computer (many Ford, GM and Volkswagen vehicles), the charging voltage changes on purpose depending on temperature and battery condition, and it can rise above 15 V when cold for a few minutes. The P0563 code appears when voltage goes beyond that margin or stays high for too long.

P0563 code symptoms

  • Headlights that are very bright or that burn out.
  • Battery acid smell.
  • Several warning lights on.

Likely causes of the P0563 code

  1. Defective alternator regulator. It charges without a limit.
  2. Bad connection on the regulator sense line. The regulator thinks voltage is low and overcharges.
  3. Battery with an internal short. It disturbs the regulation.
  4. External charger left connected or a jump start done wrong.

How to diagnose the P0563 code step by step

  1. Measure voltage with the engine at 2,000 rpm. It should not exceed about 14.7 V.
  2. Check the alternator sense connection.
  3. Test the battery.

How to fix the P0563 code

  • Replace the regulator or the alternator.
  • Replace the battery if it was damaged.
  • Clear the code and verify the repair.

Technical reference data

  • Normal maximum charging voltage: about 14.7 V (somewhat higher when cold on smart charging systems).
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

On vehicles with a computer-controlled alternator, the fault can be in the alternator control signal rather than in the regulator itself.

Frequently asked questions about P0563

Can I drive with the P0563 code?
Only when you have to. Overvoltage damages the battery and the electronics, so get it checked as soon as you can.
What usually fails?
The alternator regulator. It is the part that limits charging voltage, and when it fails the alternator charges without a limit.
Can it damage the computer?
Yes, if the overvoltage continues. Modules and bulbs are built for a limited voltage range, and sustained high voltage can burn them out.
How much does it cost to fix P0563?
Between $100 and $700, depending on whether you need a regulator, a full alternator or a new battery as well.
What does the P0563 code mean?
The P0563 code is a generic OBD2 code that means system voltage is too high, often above 15.5 to 16 V with the engine running. The usual cause is the alternator regulator.

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