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P0563 – System Voltage High (OBD2)

P0563 means "System Voltage High". The alternator charges the battery and powers the electrical system while the engine runs; these codes mean the system voltage, the alternator control or the battery temperature sensor is out of range.

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P0563 quick summary

Fault codeP0563
MeaningSystem Voltage High
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Only briefly. With low charging voltage the battery drains and the engine can stop; with high voltage electronics can be damaged. Have it checked immediately.
Repair cost€0 – €600

How the charging system is monitored

A healthy charging system holds the system voltage at about 13.8–14.8 V with the engine running. Many modern cars control the alternator output electronically (smart charging) depending on battery state, temperature and load, using a battery sensor on the negative terminal and an alternator control signal.

Codes P0560–P0563 report that system voltage is faulty, unstable, too low or too high; P0620–P0626 cover the alternator's control, field and lamp circuits; P0514–P0517 the battery temperature sensor.

Low voltage causes starting problems and many random fault codes in other modules; high voltage can damage electronics and boil the battery. Worn alternator brushes and regulators, slipping belts, bad grounds and ageing batteries are the usual causes.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 16947 (P0563). Both numbers mean the same fault.

Symptoms of P0563

  • Battery warning light on
  • Slow cranking or no start
  • Dim or flickering lights
  • Many random fault codes in different modules
  • Battery smell or swelling (overcharging)

Most common causes of P0563 (most likely first)

Mechanic's Pro Tip

After replacing a battery on many modern cars, register it with a scan tool. Otherwise the smart charging system keeps charging it like the old battery, which shortens its life and can bring charging codes back.

  1. 1.Worn alternator regulator or brushes

    Most likely

  2. 2.Weak or failed battery

  3. 3.Loose or corroded battery terminals or ground straps

  4. 4.Slipping or worn drive belt

  5. 5.Faulty battery sensor or alternator control wiring

Step-by-step diagnostic guide

  1. 1

    Measure the battery and charging voltage

    Measure the battery voltage with the engine off and with it running at idle and at 2,000 rpm.

    Multimeter: Engine off: about 12.4–12.7 V. Engine running: about 13.8–14.8 V (smart charging systems may vary between about 12.5 and 15 V).

  2. 2

    Load-test the battery

    Test the battery with a proper tester; a weak battery can make a good alternator look bad.

  3. 3

    Check terminals, grounds and belt

    Clean and tighten terminals, check the engine and body ground straps and inspect the drive belt and tensioner.

  4. 4

    Measure voltage drop

    Measure voltage drop on the positive and ground cables while the alternator is loaded.

    Multimeter: Each side should drop less than about 0.3 V under load.

  5. 5

    Check alternator control and battery sensor

    Check the alternator control signal and battery sensor with the scan tool; replace the alternator or regulator if output is wrong.

Frequently asked questions

Can I keep driving with P0563?

Only briefly. With low charging voltage the battery drains and the engine can stop; with high voltage electronics can be damaged. Have it checked immediately.

How much does it cost to fix P0563?

Typical repair costs are 0 € – 600 €, depending on the cause and the vehicle. The most common fixes are: worn alternator regulator or brushes; weak or failed battery; loose or corroded battery terminals or ground straps. Always confirm the cause with the tests above before buying parts.

Can a bad battery cause charging system codes?

Yes. A battery with an internal fault can pull the system voltage down or make it unstable.

How long can I drive with the battery light on?

Only until the battery is empty – often less than an hour. Turn off unnecessary consumers and head to a workshop.

What is the difference between P0563 and similar codes?

P0563 belongs to a group of codes for the same component that differ in the type or location of the fault: P0560 – System Voltage Malfunction; P0561 – System Voltage Unstable; P0562 – System Voltage Low; P0620 – Generator Control Circuit Malfunction; P0622 – Generator Field F Control Circuit Malfunction; P0625 – Generator Field Terminal Circuit Low. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.