🧭 Diagnostic Flowchart 🎬 Helpful Videos 🛍️ Shop This Part

P0563 on 2016-2021 Hyundai Tucson: System Voltage High Causes and Fixes

Q: Is there a recall for the electrical issues causing P0563 on my 2016-2021 Hyundai Tucson?

While there is no specific recall for the P0563 high voltage code, there is a major related safety recall (Recall 20V543000) for 2016-2021 Tucsons regarding the ABS module (HECU). An internal short in that module can cause an engine compartment fire, even when the vehicle is off.

Q: My 2016 Tucson is hesitating and shifting roughly; could this be related to the P0563 code?

Yes. A P0563 code indicates high system voltage, which can cause the transmission to enter 'limp mode' or shift incorrectly. However, 2016-2018 models with the 1.6L Turbo engine also have a known issue with the 7-speed DCT involving hesitation, addressed by Recall 149 (TSB 16-01-038).

Q: Can I just replace the voltage regulator on my Tucson's alternator to fix the overcharging?

No. On this vehicle, the voltage regulator is internal to the alternator and is not typically sold as a separate component. The recommended fix is to replace the entire alternator assembly (Part #37300-2E820 for 2.0L models).

Q: Why are my headlights flickering and my radio rebooting on my 2017 Tucson?

These are classic symptoms of P0563. When the internal voltage regulator fails, it allows excessive voltage (often above 15.5V) to flood the system, causing electronics like the radio and navigation to malfunction or reboot to protect themselves.

Q: Is the P0563 code covered under the same extended warranty as the engine failure issues?

No. The 15-year/150,000-mile extended warranty (Recall 21V727000) specifically covers connecting rod bearing failure in Theta II and Nu GDI engines, which typically triggers code P1326, not the high-voltage P0563 code.

Q: Could a bad ground cause a high voltage reading on my Hyundai?

Yes. Poor connections at the battery terminals or chassis grounds can cause the alternator's voltage sense circuit to read incorrectly. This leads the alternator to overcompensate and produce excessive voltage, triggering the P0563 code.

P0563 on a 2016-2021 Tucson indicates the charging system voltage is too high, typically exceeding 15.5V. This is almost always caused by a failing alternator with a bad internal voltage regulator. Replacing the alternator is the typical fix. Sustained high voltage can damage sensitive electronics, so it should be addressed promptly.

20 minutes to read 2016-2021 Hyundai Tucson

Most Likely Cause

Failing Alternator / Internal Voltage Regulator

Difficulty

3/5

Est. Time

2 hrs

DIY Doable?

✅ Yes

Shop Labor

$475 – $1030

Parts Price

$250 – $815

⚠️ Drivable, but... — It is not recommended to drive for an extended period. A sustained high-voltage condition can damage sensitive and expensive electronics, including the PCM, instrument cluster, and audio system. In some cases, high voltage spikes can cause the engine to stall or electronic modules like power steering to fail intermittently.

Key Takeaways

P0563 means your Tucson's charging system is producing dangerously high voltage.
The most common cause by far is a failed alternator with an internal voltage regulator fault.
Confirm the problem by testing the voltage at the battery with the engine running. A reading over 15V indicates an overcharging alternator.
Address this issue promptly to avoid expensive damage to other electronic modules in the vehicle.
Ensure you purchase the correct alternator for your specific engine (1.6L, 2.0L, or 2.4L) as they are not interchangeable.

The trouble code P0563 stands for 'System Voltage High'. On a 2016-2021 Hyundai Tucson, this means the Powertrain Control Module (PCM) has detected that the electrical system's voltage is above the normal operating range. Typically, the PCM expects to see a voltage between 13.2 and 14.8 volts when the engine is running. This code is set when the voltage exceeds a specific threshold, often above 15.5V or 16V, for more than a few moments, indicating an overcharging condition. One source notes a similar platform triggers the code when voltage is over 17V for just 0.2 seconds.

What's Unique About the 2016-2021 Hyundai Tucson

For the third-generation (TL) Hyundai Tucson, the P0563 code is a straightforward electrical fault. There are no widespread recalls or technical service bulletins (TSBs) specifically for this code, suggesting it's a standard component failure rather than a systemic design flaw. The most critical factor for this platform is ensuring the correct alternator is used for the specific engine (1.6L Turbo, 2.0L, or 2.4L), as they have different amperage ratings and part numbers. The platform-mate Kia Sportage experiences the exact same failure mode.

Symptoms You May Notice

Check Engine Light is on
Battery or charging system warning light is illuminated
Headlights and interior lights are unusually bright or flickering
Malfunctioning or rebooting electronics (radio, navigation, etc.)
Engine may hesitate or stall, sometimes with difficulty restarting
A burning smell from the alternator or battery
Transmission may not shift correctly or enter 'limp mode'
Gauges on the instrument cluster behaving erratically

⚠️ Don't Waste Money on the Wrong Fix

Replacing the battery without first testing the alternator. A new battery will soon be subjected to the same overcharging condition if the alternator is the root cause.
Replacing the alternator without checking for a bad ground or corroded terminal first. While less common, a bad connection is a much cheaper fix.
Assuming a remanufactured alternator is good. There are documented cases where a newly installed remanufactured alternator was also faulty, causing the P0563 to persist.

Most Likely Causes

Failing Alternator / Internal Voltage Regulator 🔴 High Probability → Shop Voltage Regulator The voltage regulator, which is responsible for capping the alternator's output, is internal to the alternator. When it fails, it allows unregulated, excessive voltage to flood the system. This is the most common failure mode that triggers a P0563 code.
How to confirm: With the engine running, use a multimeter to measure the DC voltage across the battery terminals. A healthy system should read between 13.2V and 14.8V. If the reading is consistently above 15.0V (and especially if it exceeds 15.5V), the alternator is overcharging and has failed. Also check for excessive AC ripple voltage, which indicates a failing diode inside the alternator.
Typical fix: Replace the entire alternator assembly. The voltage regulator is not typically sold as a separate component for this vehicle. 🎬 See: How to replace the voltage regulator on a Tucson alternator
Est. part cost: $250-$815
Corroded or Loose Battery Terminals/Grounds 🟡 Medium Probability → Shop Vehicle Battery While not a specific design flaw, poor connections can cause the alternator's voltage sense circuit to read incorrectly and overcompensate. It's a common issue on all vehicles and an easy first check.
How to confirm: Visually inspect the battery terminals, main chassis ground, and engine block ground strap for looseness, corrosion, or damage. Clean and tighten all connections. A poor ground can cause the alternator to sense low voltage and overcompensate, creating a high voltage condition.
Typical fix: Clean the battery terminals and cable ends with a wire brush. Ensure all connections are tight and secure. Apply dielectric grease to prevent future corrosion.
Est. part cost: $5-$15
Faulty Battery ⚪ Low Probability → Shop Vehicle Battery
How to confirm: An internally shorted or failing battery can sometimes cause the charging system to behave erratically and overcompensate. Most auto parts stores can perform a load test on the battery for free to determine its health.
Typical fix: Replace the battery if it fails a load test.
Est. part cost: $150-$300

Rare But Worth Checking

Powertrain Control Module (PCM) Failure: → Shop Engine Control Module (ECM) This is very rare. The PCM's voltage sensing circuit can fail, causing it to misread the system voltage and set a false P0563 code. This should only be considered after the alternator and all wiring have been confirmed to be in perfect working order.
Wiring Harness Damage: On some Hyundai platforms, there are known issues with wiring harnesses chafing against brackets, particularly near the transmission. A short in the voltage-sense wire could cause the PCM to command excess alternator output. This should be investigated if a new alternator does not solve the problem.

Diagnosis Steps

Read the code with an OBD-II scanner and check for any other related codes. Record the freeze-frame data to see the conditions when the code was set.
Visually inspect the battery terminals, main power cables, and ground straps for any signs of corrosion, damage, or looseness. Clean and tighten as necessary.
With the engine off, use a multimeter to check the battery's static voltage. It should be approximately 12.4V-12.6V.
Start the engine. Measure the voltage at the battery terminals again. The reading should be stable, between 13.2V and 14.8V.
If the voltage is above 15.0V, and especially if it's spiking above 15.5V, the alternator's voltage regulator has likely failed.
To confirm, turn on heavy electrical loads like the headlights, high beams, and HVAC fan on high. The voltage should remain stable within the normal range. If it spikes or becomes erratic, this further confirms a faulty alternator.
If possible, use a multimeter with an AC setting to check for AC ripple voltage at the battery terminals while the engine is running. More than 0.5V AC suggests failing diodes in the alternator.
If the alternator tests good but the code persists, carefully inspect the wiring harness between the alternator and PCM for chafing or damage, particularly near brackets.

Parts You'll Likely Need

Alternator (OEM #37300-2B960) — This is the most common failure. The internal voltage regulator fails, causing the overcharging condition. This part number is for the 1.6L Turbo engine (2016-2018).
Trusted brands: Hyundai (OEM), Mando (OE Supplier), Bosch, Valeo, Denso
OEM price range: $600-$800
Aftermarket price range: $250-$500
Alternator (OEM #37300-2E820) — This is the most common failure. The internal voltage regulator fails, causing the overcharging condition. This part number is for the 2.0L engine and is also used on the Kia Sportage and Soul.
Trusted brands: Hyundai (OEM), Mando (OE Supplier, P/N BN373002E820), Valeo (OE Supplier, P/N 2624670), Denso, Bosch
OEM price range: $560-$795
Aftermarket price range: $280-$450
Alternator (OEM #37300-2G051) — This is the most common failure. The internal voltage regulator fails, causing the overcharging condition. This part number is for the 2.4L engine (2018-2021).
Trusted brands: Hyundai (OEM), Mando (OE Supplier), Bosch, Valeo, Denso
OEM price range: $680-$975
Aftermarket price range: $300-$550

Related Codes That Often Appear With This One

P0562 — System Voltage Low. It's possible for a failing alternator or bad wiring to cause both voltage spikes (P0563) and drops (P0562) as it fails.
P0620 — Generator Control Circuit Malfunction. This code points more directly to a fault within the alternator's control system, which is often the root cause of the P0563 overcharging issue.

Platform-Specific Known Issues

A YouTube video titled 'P0563, KIA SPORTAGE ACTIVE HYUNDAI TUCSON DEMASIADO VOLTAJE EN EL CIRCUITO' documents this exact issue on a platform mate. The vehicle showed 17+ volts, causing engine hesitation and warning lights. The fix was replacing the voltage regulator (or in most US cases, the entire alternator).

Mechanic-Grade Diagnostic Values

Normal Charging System Voltage at Battery Terminals (Engine Running) — expected: 13.2V - 14.8V DC. Failure: Consistently above 15.0V, especially spiking to 15.5V or higher.
P0563 Fault-Setting Threshold (Hyundai-specific) — expected: Voltage > 16.9V - 17V for more than 0.2 seconds.. Failure: This condition being met will log the P0563 code in the ECM.
Voltage Drop Test (Ground Side) — expected: < 0.3V DC. Failure: A reading higher than 0.3V between the negative battery terminal and the alternator case indicates high resistance in the ground circuit.
Voltage Drop Test (Power Side) — expected: < 0.2V DC. Failure: A reading higher than 0.2V between the positive battery terminal and the alternator's B+ output stud indicates high resistance in the power feed cable.
Alternator AC Ripple Voltage — expected: < 0.5V AC. Failure: A reading greater than 0.5V AC at the battery terminals with the engine running suggests failing diodes inside the alternator.

Scan Tool Commands That Help

Hyundai GDS (Global Diagnostic System): Live Data / Data Stream - 'System Voltage' — Use this to monitor the voltage that the ECM is seeing in real-time. It helps confirm if the ECM's reading matches a multimeter reading at the battery, which can help rule out a PCM input fault.
Hyundai GDS or Advanced OBD-II Scanner: ECM/PCM Self-Test or Voltage Sensor Test — This internal module test should be used if the alternator, battery, and all wiring test good, but the P0563 code persists. A failure here points to a rare internal PCM fault.
Hyundai GDS (Global Diagnostic System): Guided Troubleshooting Procedures — For a factory-prescribed diagnostic path, the GDS software provides a step-by-step tree for P0563, prompting the technician to check specific connections and values in the correct order.

Wiring & Ground Locations

Alternator B+ Terminal — The large threaded stud on the back of the alternator, typically under a black or red rubber boot.. This is the main output point of the alternator. Voltage should be tested here to compare against battery voltage to check for voltage drops in the main power cable.
Engine/Chassis Ground Point — A common and accessible ground point is one of the nuts on top of the driver's side strut tower in the engine bay.. This is a known-good chassis ground point suitable for testing and jump-starting. A voltage drop test between the negative battery post and this point can help verify the quality of the main ground connection.
Main Engine Ground Strap — Generally a braided, uninsulated metal strap connecting the engine block or transmission case to the vehicle's chassis, often on the driver's side frame rail.. This is the primary return path for the charging system current. Corrosion or looseness here can cause high resistance, leading to erratic charging behavior and potentially triggering a P0563.

Real Owner Repair Stories

Go-Parts repair guide, citing a forum user (2017 Hyundai Elantra (6th gen, 2.0L Nu engine)) — Vehicle stalling, P0563 code stored, measured system voltage was over 17V.
✅ What actually fixed it The dealership confirmed a failed alternator and replaced the entire unit under warranty, which resolved the issue.

"I Checked Everything" — The Actual Cause

In cases where the P0563 code persists after replacing both the alternator and the battery, the root cause has been found to be poor ground connections. A thorough inspection, cleaning, and tightening of the main ground straps to the chassis and engine block resolved the high voltage condition when new parts did not.

Diagnostic Flowchart

P0563 indicates a System Voltage High condition. On the Tucson platform, this is often caused by a failing internal voltage regulator in the alternator, which can send over 15V through the sensitive electronics.

With the engine running, measure DC voltage across the battery terminals. What is the reading?

The voltage regulator has likely failed. On the 2016-2021 Tucson (Nu 2.0L or Theta II 2.4L), the regulator is internal. Do you smell burning or see an 'Alternator' warning light?

→ Replace the alternator assembly (Part #37300-2E820 for 2.0L models). The internal regulator is not serviced separately. High voltage can damage the PCM if not addressed.

→ Perform an AC Ripple test using a multimeter. If AC voltage exceeds 0.5V, the alternator diodes are failing. Replace the alternator assembly.

Turn on high beams, HVAC fan on high, and rear defroster. Does the voltage remain stable under load?

→ The alternator is failing to regulate under load. Replace the alternator assembly to prevent damage to the Tucson's electronic modules.

Is the battery more than 3-4 years old or showing signs of swelling?

→ An internally shorted battery can cause charging system instability. Have the battery load-tested at an auto parts store; replace if it fails.

The charging system hardware tests good. Have you checked for wiring damage?

→ Inspect the wiring harness between the alternator and PCM for chafing, especially near engine brackets. Also, ensure Recall 20V543000 (ABS Module Short) has been performed, as internal HECU shorts can cause unpredictable electrical issues on this platform.

Inspect the battery terminals and the main chassis ground. Is there heavy corrosion or loose connections?

→ Clean battery terminals and cable ends with a wire brush. Tighten all connections and apply dielectric grease. A poor ground can cause the alternator to overcompensate, triggering P0563.