P0563 fault code: high system (battery) voltage
Plain-language definition
System Voltage High
What does it mean?
While the engine is running, the alternator powers the electrical system and charges the battery; the voltage regulator keeps this charging voltage within a set range. On some newer cars, the car's control units manage the charging voltage based on information from the battery sensor.
The engine computer constantly measures its supply voltage; if the voltage stays above the upper limit for a set time, it stores P0563. The most common cause is a failed regulator that can no longer limit the charge. Using a device that puts out high voltage during a jump-start can also leave this code behind as a past record.
You may notice the headlights shining brighter than normal, bulbs blowing often, the battery warning light, the battery overheating or a sharp smell coming from the battery. The 2dakika report may also show the battery voltage; but when the scan is done without the engine running, this value doesn't show the charging voltage, so on its own it may not reflect this problem.
How serious is it?
It's rated Warning, but if the high charging voltage continues, the battery can be damaged and electronic modules can be put under strain. That's why it's important to find the cause early.
Severity is a guide; if the warning light is flashing or you notice symptoms while driving, have the car checked at a workshop.
Common general causes
- A failed voltage regulator in the alternator
- On cars where control units manage charging, a problem with the battery sensor or the charging control line
- A problem in the line the engine computer uses to measure voltage, or in the ground connection (a false reading)
- High voltage applied to the car during a jump-start or charging
- Less often, a fault in the engine computer itself
The list shows general causes; a workshop finds the actual cause on your car with a check.
Definitions by make
Some manufacturers record the same code under their own wording:
- Honda
- Engine Control Module (ECM)/Powertrain Control Module (PCM) Power Source Circuit Unexpected Voltage
- Isuzu
- PCM or TCM constant power supply voltage high
Related codes
How does it appear in the 2dakika report?
System Voltage High
If the code is read as a confirmed (stored) fault, the report shows it with the "Warning" severity; in pending or past records, codes that don't request the warning light and aren't critical appear as "Info". If the engine computer stored them, the conditions when the fault was recorded (engine temperature, rpm, speed) are shown too.
Read this code with the OBD-X1, and clear it from the app after the repair.
Clearing the code doesn't fix the fault; if the problem persists, the code comes back.