Recall 18V166 affects 2,840 2016-2018 Hyundai Sonata Plug-In Hybrid vehicles for inadvertent Voltage Protection Device activation. Repair is free at any franchised Hyundai dealer.
Hyundai is recalling 2,840 2016-2018 Sonata Plug-In Hybrid vehicles because the Voltage Protection Device can activate while the vehicle is being driven in EV mode. If that happens, the vehicle can lose power and increase crash risk; Hyundai dealers will repair the system free of charge.
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What's wrong?
The 2016-2018 Hyundai Sonata Plug-In Hybrid uses a high voltage battery to help power the hybrid propulsion system. Hyundai equipped these vehicles with a Voltage Protection Device, or VPD, to protect the high voltage battery module. Its job is to act as a safety switch when the battery system needs protection.
On affected Sonata Plug-In Hybrid vehicles, the VPD switch can activate when it should stay on. Hyundai traced the condition to inadvertent activation of the VPD switch by the hybrid battery. That false activation makes the vehicle respond as if the battery protection system has detected a fault, even though the switch action is not the intended behavior.
The warning sign is a "Check Hybrid System" lamp in the instrument cluster. If that light appears, the vehicle is giving the driver the warning Hyundai identified for this recall.
Who's affected?
Spans the 2016, 2017, and 2018 model years, all tied to the hybrid propulsion system.
| 2018 Hyundai Sonata Plug-In Hybrid | Hybrid propulsion system |
|---|---|
| 2016 Hyundai Sonata Plug-In Hybrid | Hybrid propulsion system |
| 2017 Hyundai Sonata Plug-In Hybrid | Hybrid propulsion system |
| Units affected | 2,840 |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific sedan is included.
What's the safety risk?
If the VPD activates while the Sonata Plug-In Hybrid is operating in EV mode, the vehicle can lose power, increasing the risk of a crash. The Check Hybrid System warning lamp will illuminate in the instrument cluster. If that warning appears, drive cautiously, move out of traffic, and arrange service soon. Repair is free at any franchised Hyundai dealer.
What should I do?
- Check your VIN to confirm your 2016-2018 Hyundai Sonata Plug-In Hybrid is included in this recall.
- Contact your nearest franchised Hyundai dealer to schedule the free VPD switch removal and BMS installation, which adds overvoltage protection for the high-voltage battery.
- Bring any Hyundai owner letter you received. If you do not have one, reference recall number 18V166 when you call.
- Drive cautiously until the repair is complete, and leave extra following distance in case the vehicle loses power in EV mode.
What happens at the repair
At the dealer, a Hyundai technician removes the Voltage Protection Device switch and installs a new Battery Management System that includes an Overvoltage Protection Device. The replacement parts and labor are free under the recall. If you've already paid out of pocket for this repair, Hyundai provides reimbursement under its submitted reimbursement plan. Ask the service desk or Hyundai customer service how to submit repair documentation for review.
| Reimbursement | Reimbursement available |
|---|
Timeline
| March 12, 2018 | NHTSA published the recall |
|---|---|
| March 16, 2018 | Dealer notification began |
| March 16, 2018 | Dealer notification ended |
| May 2, 2018 | Owner notification mailed |
| May 4, 2018 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| May 4, 2018 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 18V166?
Recall 18V166 covers 2,840 2016-2018 Hyundai Sonata Plug-In Hybrid vehicles with a voltage protection device that can activate while the car is in EV mode. If that happens, the vehicle can lose power and raise crash risk. Hyundai dealers will remove the VPD switch and install a new battery management system for free.
What should I do if my 2016-2018 Hyundai Sonata Plug-In Hybrid is on this recall?
Check your VIN to confirm your specific vehicle is included in recall 18V166. If it is, contact a franchised Hyundai dealer to schedule the repair. Reference Hyundai recall number 175 when you call. The dealer repair is free.
Is the recall repair free?
Yes. Federal recall law requires Hyundai to repair this defect at no cost. A franchised Hyundai dealer will remove the VPD switch and install a new battery management system with an overvoltage protection device free of charge.
What is the safety risk?
The safety risk is loss of power while driving in EV mode. The recall filing says an inadvertent VPD activation can shut down power and increase crash risk. If your VIN is included, schedule the free Hyundai dealer repair.
What if I bought my Hyundai Sonata Plug-In Hybrid used?
The free repair still applies. Recall coverage follows the vehicle, not the first owner. Check your VIN to confirm whether your specific Sonata Plug-In Hybrid is included, then contact a franchised Hyundai dealer and reference recall 18V166 or Hyundai recall number 175.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/18V166000 |
|---|---|
| Hyundai customer service | 1-855-371-9460 |
| NHTSA recall # | 18V166 |
| NHTSA recall # (full) | 18V166000 |
Source documents
-
Download Misc. Document (PDF) - Download Recall Document (PDF) (PDF)
- Download Owner Notification Letter (PDF)
- Download Owner Notice (PDF)
- Download Recall Report (PDF)
- Download Quarterly Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 25, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →