Fault code P0563 – a step-by-step guide to diagnosing and fixing it

Error code P0563 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected that the vehicle electrical system voltage is too high and exceeds the normal operating range of 12-14.4 volts. This DTC P0563 "System Voltage High" affects the entire electrical system of the vehicle and can affect various control units. For various manufacturers, this fault code may also be referred to as "Battery Voltage High" or "Charging System Voltage Too High".

What causes can this error code have?

• Defective alternator with excessive charging voltage
• Defective voltage regulator of the alternator
• Damaged or corroded battery cables
• Defective vehicle battery with internal short circuit
• Loose or corroded earth connections
• Defective control unit power supply
• Damaged wiring in the charging system
• Defective fuses or relays in the circuit

What symptoms occur in parallel with fault code P0563?

• Electrical problems: Flickering or unusually bright lights, defective electronic components due to overvoltage
• Battery problems: Overheated battery, boiling battery fluid or premature battery wear
• Engine performance: irregular engine running, starting problems or sudden engine stalling
• Electronics failure: Malfunctioning radio, navigation, air conditioning or other electrical consumers
• Warning lights: Additional indicator lights for battery or charging system may light up

How can the problem with error code P0563 be rectified?

• The repair requires a systematic check of the entire charging system to identify the cause of the overvoltage.
• Check the alternator and voltage regulator and replace them completely if they are defective, as these are usually the main cause of overvoltage
• Clean and tighten all battery cables and earth connections and replace if corroded or damaged
• Fully test the vehicle battery and replace with a new battery if there is an internal defect or loss of capacity
• Carry out voltage measurements at various points in the electrical system and repair or replace defective cables
• Check all fuses and relays in the charging system and replace defective components
• Check control units for overvoltage damage and program or replace if necessary