P0563

What P0563 Means

Code P0563 (System Voltage High) points to excessive voltage in the vehicle's electrical system. The DME logs voltage above the allowed threshold, which can come from a faulty alternator voltage regulator or a problem with the battery.

The charging system includes the alternator with its built-in voltage regulator, the battery, and the wiring. The regulator holds voltage within spec; when it fails, voltage can climb and hit every electronic module and light on the car.

Symptoms

• Warning light: Check Engine is on.
• Electrical equipment: bulbs burn out (overvoltage shortens their life or kills them outright).
• Electronics: electronic systems act up (glitches, errors, and control modules that don't function correctly are all possible).

Diagnosis and Repair

1. Check the alternator and voltage regulator: measure voltage at the battery terminals with the engine running. Voltage above spec points to a bad regulator. Replace the regulator, or the alternator as a unit, if needed.
2. Check the battery: inspect the battery's condition and voltage, and confirm there's no shorted cell or sulfation that could affect how the charging system works.

Use a multimeter to measure voltage. While diagnosing, use ISTA or INPA to read related faults and live voltage data.

Related Problems

Running for a long time with high system voltage speeds up wear and failure of bulbs and damages sensitive electronics (control modules, sensors, infotainment). Ignoring the fault can cause cascading electrical failures and raises the risk of fire. Do the repair right away.