P0563 System Voltage High

P0563 indicates system voltage is higher than expected. The charging system or voltage-sensing circuit may be exceeding the control module's allowable range.

Code details

Generic OBD-II · P0

System: Speed / Idle
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not keep driving with overvoltage present; excessive system voltage can damage modules, sensors, and the battery.

Symptoms of P0563

Unstable, high, or low idle, or stalling.
Erratic speedometer, cruise-control, or shift behaviour.
Check-engine light with a hesitation or surge.

Common causes of P0563

A dirty throttle body, idle-control valve, or throttle-position sensor.
A failing vehicle-speed or wheel-speed sensor, or its wiring.
Vacuum leaks or a related sensor forcing the idle/speed strategy.

Useful checks before replacing parts

Measure charging voltage at the battery and compare it with scan-tool system voltage under different loads.
Inspect alternator control wiring, battery terminals, grounds, fusible links, and voltage-sense circuits.
Review recent battery, alternator, jump-start, or charging-system work that may have changed voltage behavior.

Related OBD-II codes

These nearby speed / idle entries can help compare wording and pin down the fault area.