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P0563: System Voltage High

What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.

Severity: Urgent — high voltage can damage electrical components

What P0563 means

This code means the powertrain control module (PCM) has detected that the vehicle's electrical system voltage is consistently above the normal operating range (typically above 16 volts). Excessive voltage can damage sensitive electronic components, the battery, and other electrical systems throughout the vehicle.

What causes P0563?

Likely
Faulty voltage regulator or alternatorA malfunctioning voltage regulator (often built into the alternator) is overcharging the electrical system.
Likely
Defective PCM or wiring issueCorroded or damaged wiring between the alternator and PCM, or a faulty PCM voltage sensing circuit.
Possible
Poor battery or battery connectionsA failing battery or loose/corroded battery terminals can cause voltage regulation problems.
Less common
Aftermarket electrical accessoriesImproperly installed high-draw accessories or modifications interfering with the charging system.

Is P0563 safe to drive?

Drive it?
Not recommended for extended periods
Watch for
Burning smell, dimming/flickering lights, battery warning light
DIY-friendly?
Check battery terminals and voltage; alternator testing requires equipment

You can drive briefly to a repair facility, but prolonged driving with high system voltage risks damaging the battery, PCM, and other electronic modules. Have the charging system inspected immediately to prevent costly electrical component failures.

P0563 repair cost

~$150 – $800+

Industry-average estimates. Cost depends on whether you need just a voltage regulator, a complete alternator replacement, or PCM/wiring repairs.

Which one is it for your car?

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