Speed, idle & inputs · Powertrain · generic (SAE-defined)
P0563: System Voltage High
P0563 means the engine computer has detected that the electrical system voltage is higher than normal, usually from a charging system that is overcharging.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0563 sets
The powertrain control module (PCM) monitors its supply voltage. If voltage stays above a maximum calibrated value for a set time with the engine running, it sets P0563. The threshold varies by manufacturer.
Common causes of P0563
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Faulty voltage regulator or alternator
- Poor voltage sense connection to the alternator
- Bad ground causing incorrect regulator readings
- Improper jump-starting or charger connection
- Faulty battery current sensor on smart charging systems
P0563 symptoms
- Check engine light on
- Battery or charging warning light
- Very bright or flickering lights
- Bulbs burning out frequently
- Battery swelling or a sulfur smell
How P0563 is diagnosed
- Measure battery voltage with the engine running and compare to specification
- Inspect alternator sense and control wiring
- Check engine and body grounds
- Test the alternator and voltage regulator
- On smart charging systems, check the battery current sensor and charging control codes
Typical fixes for P0563
- Replace the alternator or voltage regulator
- Repair sense or ground wiring
- Replace a damaged battery
- Replace a faulty battery current sensor
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Manufacturer notes
Definitions can vary by manufacturer; check factory service information.
Related codes & warning lights
P0563 FAQ
What does code P0563 mean?
P0563 means the engine computer has detected that the electrical system voltage is higher than normal, usually from a charging system that is overcharging. The standard definition is "System Voltage High."
Can I drive with a P0563 code?
Limit driving and get it checked promptly. Overcharging can overheat and damage the battery and electronic modules, and can blow bulbs or fuses. If you smell a rotten-egg or burning odor from the battery, stop driving.
Can a jump start cause P0563?
A voltage spike during an improper jump start can set the code. If it does not return after clearing, it may have been a one-time event.
Is overcharging bad for the battery?
Yes. Excess voltage can boil the electrolyte, warp internal plates, and shorten battery life significantly.
Keep researching
More speed, idle & inputs codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.