AutoCodes – GMC – P0563 GMC

P0563 GMC Code - System Voltage High

Quick Answer

The Powertrain Control Module (PCM) continuously monitors the system voltage. Common causes include Battery defective, Loose or missing alternator drive belt, Faulty alternator. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0563 GMC indicates System Voltage High.
Common causes: Common causes include Battery defective, Loose or missing alternator drive belt, Faulty alternator.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 4,267

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 04, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0563 GMC Description

The Powertrain Control Module (PCM) continuously monitors the system voltage. The system voltage information is taken from the PCM's ignition feed circuits. Voltages below 8.0 volts or above 17.1 volts cause improper system operation and/or component damage. If the system voltage is low the PCM raises the idle speed in order to increase the generator output. The PCM disables most outputs to protect the hardware if the system voltage is high. A scan tool may not display data if system voltage is outside this range. The Diagnostic Trouble Code (DTC) will be set if the PCM detects that the electrical system voltage level is too high.

OBDII Code P0563 GMC - System Voltage High - AutoCodes.com — P0563 GMC Code - System Voltage High

What does this mean?

What are the Possible Causes of the DTC P0563 GMC?

Battery defective
Loose or missing alternator drive belt
Faulty alternator
Open or short system voltage circuit

How to Fix the DTC P0563 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Higher than expected voltage problems are most likely caused by bad voltage regulator. The voltage regulator is part of the alternator.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0563 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0563 GMC code?

Need more information on how to fix the P0563 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific GMC Models

P0563 2014 GMC Sierra — System Voltage High
P0563 2015 GMC Sierra — System Voltage High
P0563 2016 GMC Sierra — System Voltage High
P0563 2017 GMC Sierra — System Voltage High
P0563 2018 GMC Sierra — System Voltage High

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.