AI-powered OBD-II fault code diagnostic tool for UK drivers
P0563

P0563 System Voltage High

P0563 indicates system voltage high. The exact repair depends on whether the underlying issue is a sensor fault, wiring problem, mechanical wear, or a related system problem on the vehicle being diagnosed.

Last reviewed 14 June 2026 AI-Diagnostics-Pro Editorial Team

This guide is reviewed against current UK fault-code usage patterns, MOT guidance, and indicative repair-cost context. It is educational guidance for P0563, not a substitute for live data, workshop testing, or a final quote.

Editorial policy UK MOT guide DVSA MOT inspection manual
UK Repair Cost
£50–£400
MOT Risk
May affect MOT — get it checked
Safe to Drive?
Drive with caution and get it checked — high voltage can damage electronics and the battery.

At a glance: P0563 for UK drivers

Fault family
General powertrain diagnostics
Best first check
Check for related codes before authorizing repairs.
Typical garage risk
The main risk with P0563 is treating the code description as a final diagnosis. Fault codes point to a system or behavior, not always the exact failed component.

How to use this page

This page explains the code in plain English and gives indicative UK repair and MOT context. It does not confirm the exact failed part. Vehicle age, engine, related codes, live data, and workshop inspection can all change the final diagnosis and quote.

What does fault code P0563 mean?

P0563: charging system voltage too high, can damage electronics. Check alternator, regulator and battery first (£50-£400). When this fault is detected, the ECU (Engine Control Unit) stores the code and usually illuminates the check engine light on the dashboard.

In practice, P0563 should be treated as a general powertrain diagnostics problem first, not as proof that one named part has failed. The value of the code is in narrowing the system, checking related data, and avoiding the usual misdiagnosis before parts are ordered.

Symptoms of fault code P0563

These are the most common symptoms UK drivers report when this code is active:

  • Check engine light on
  • Electrical system voltage too high
  • Overcharging warning
  • Battery overheating or swelling
  • Possible electrical component damage

Note that some vehicles show no drivability symptoms at all — the check engine light may be the only sign. This is why scanning the fault code is essential rather than guessing at the cause.

What causes P0563?

These are typical causes to check first:

  1. Faulty voltage regulator (built into alternator)
  2. Alternator overcharging
  3. Wiring fault in charging circuit
  4. Faulty battery causing the alternator to overwork

It is important to diagnose the root cause before replacing parts. Many unnecessary and expensive repairs happen because the most expensive component is replaced first without proper testing. Always work through the diagnostic steps systematically.

How to fix P0563 — step by step

Work through these steps in order to avoid unnecessary parts replacement:

  1. Check the battery voltage with a multimeter — should be 13.5V–14.5V when running
  2. If voltage exceeds 15V, the alternator voltage regulator is faulty
  3. Test the battery — a failing battery can cause the alternator to overcharge
  4. Replace the alternator if the voltage regulator is non-separable

After any repair, clear the fault code with an OBD-II scanner and carry out a test drive. If the code returns, continue to the next diagnostic step. For a personalised repair guide specific to your vehicle's make, model, year and engine, use our AI Diagnostic Report below.

UK vehicles commonly affected by P0563

These models are frequently seen with this fault code in UK garages:

  • All vehicles — overcharging is a universal issue
  • Ford Focus/Mondeo
  • Vauxhall Astra/Corsa
  • Volkswagen Golf/Passat
  • BMW 3/5 Series

This code can appear on OBD-II compatible vehicles. OBD-II is standard on most UK petrol cars from 2001 and diesel cars from 2004, with many later-1990s vehicles also compatible. The models listed above are examples where owners and garages often encounter this fault, but they are not an exhaustive or ranked list.

DIY difficulty and cost guide

Difficulty: Medium — alternator replacement is usually accessible but requires basic mechanical skill.

UK repair cost estimate: £50–£400 including parts and labour at average UK workshop rates (inc. VAT). Independent garages are typically 30–50% cheaper than main dealers. Always get at least two quotes.

Prevention: Check battery health every 3 years, inspect charging voltage periodically.

Detailed analysis for P0563

What usually triggers P0563 on UK cars

P0563 is most likely part of the System Voltage High diagnostic family, which means the code identifies a monitored system but not always the exact failed part. On UK cars the right approach is to confirm live data, wiring integrity, and related faults before replacing components.

Checks that save money before replacing parts

  1. Check for related codes before authorizing repairs.
  2. Ask for live-data evidence, not just the fault-code description.
  3. Confirm whether the issue is electrical, mechanical, or plausibility-related before buying parts.

Common misdiagnosis to avoid

The main risk with P0563 is treating the code description as a final diagnosis. Fault codes point to a system or behavior, not always the exact failed component.

Questions to ask your garage about P0563

  • What live data supports the diagnosis?
  • What related faults were found or ruled out?
  • What proves the quoted part is the actual root cause?

P0563 and the UK MOT test

Fault code P0563 does not directly cause an MOT failure on its own, but it can still cause a failure if it keeps the check engine light (MIL) on where MIL inspection applies, or affects emissions.

Even if the light is not currently on, if the fault is intermittent it could reappear during the test. Use our AI Diagnostic Report to understand the MOT risk specific to your vehicle and get advice on whether it is safe to proceed to your test.

Sources and references

This guide is informed by the following authoritative UK sources:

Repair cost estimates are based on UK labour rates and parts pricing from AA, RAC and independent garage surveys, reviewed quarterly. All content is for educational purposes and is not a substitute for professional mechanical diagnosis.

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Frequently asked questions about P0563

What does P0563 mean in plain English?

P0563 is a general powertrain diagnostics fault code. In practice, P0563 should be treated as a general powertrain diagnostics problem first, not as proof that one named part has failed. The code helps narrow the system, check related data, and avoid misdiagnosis before parts are ordered.

Will P0563 fail an MOT?

P0563 does not automatically fail an MOT on its own, but the underlying fault can still cause a failure if it affects safety, warning lights, or emissions.

Can I keep driving with P0563?

Drive with caution and get it checked — high voltage can damage electronics and the battery.

How much does it usually cost to fix P0563 in the UK?

Typical UK repair costs for P0563 range from £50–£400, depending on the underlying fault, your exact vehicle, and local labour rates.

Related guides for P0563

Use these supporting pages to compare likely repair paths, warning-light behaviour, MOT risk, and the questions to ask before approving work.

Will an engine management light fail MOT?

Related and nearby OBD2 codes

Compare P0563 with closely related faults, nearby codes in the same family, and adjacent module or sensor faults that often need to be ruled out during diagnosis.

P0562
System Voltage Low
P0700
Transmission Control System Malfunction
P0522
Engine Oil Pressure Sensor/Switch Low Voltage
P0715
Input/Turbine Speed Sensor Circuit Malfunctio…
P0505
Idle Control System Malfunction
P0506
Idle Control System RPM Lower Than Expected
P0507
Idle Control System RPM Higher Than Expected
P0520
Engine Oil Pressure Sensor/Switch Circuit Mal…
P0521
Engine Oil Pressure Sensor/Switch Range/Perfo…
P0A0F
Drive Motor A Performance
P0A09
DC/DC Converter Status Circuit Low
P0BBE
Hybrid Battery Voltage System Isolation Fault

Last updated: August 2026. AI-Diagnostics-Pro provides AI-generated information for educational purposes only. It is not a substitute for professional automotive advice. Always consult a qualified mechanic before carrying out vehicle repairs. Repair cost estimates are approximate and may vary by region and vehicle.