Recall 18V666 affects 27,030 2017-2018 Kia Niro vehicles for Power Relay Assembly overheating. Repair is free at any franchised Kia dealer.
Kia is recalling 27,030 2017-2018 Niro hybrid electric vehicles because the Main Relay inside the Power Relay Assembly has inadequate contact connections that increase electrical resistance. That resistance can overheat the rear seat above the assembly and increase the risk of a fire, so Kia dealers will inspect and repair the Power Relay Assembly free of charge.
Does this recall apply to your specific vehicle?
The official, free per-VIN recall check is run by NHTSA. Enter your VIN and we'll forward you directly — and add you to a free watchlist so you hear about new recalls for your vehicle.
Check my VIN at NHTSARecallNotify doesn't check your VIN — NHTSA's official tool does. We use your email only to alert you to new recalls.
Watch this vehicle for recalls
Add it to your free watchlist and we will alert you as new federal recalls are posted for your year, make and model. New-recall alerts are rolling out now.
You are on the watchlist.
We will email you as new federal recalls are posted for your vehicle.
What's wrong?
The main relay in the power relay assembly is part of the 2017-2018 Kia Niro hybrid propulsion system. Its job is to pass high-voltage electrical power through the hybrid system when the vehicle is ready to run. The relay contacts have to close cleanly so current flows with the right resistance.
On affected Niro vehicles, the connection between the main relay contacts is not tight enough. That poor contact increases electrical resistance, and resistance generates heat inside the power relay assembly. Heat at that connection interferes with normal power flow through the hybrid system.
Owners can see the HEV warning light come on while driving. The vehicle also can fail to start. Those are the warning signs tied to this relay problem.
Who's affected?
Included Niro crossovers were built from November 1, 2016 through September 11, 2017, with both model years tied to the hybrid propulsion system.
| 2017 Kia Niro | Hybrid propulsion system |
|---|---|
| 2018 Kia Niro | Hybrid propulsion system |
| Units affected | 27,030 |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific crossover is included.
What's the safety risk?
Higher electrical resistance in the Power Relay Assembly can overheat the rear seat area above it, increasing the risk of a fire. Treat an HEV warning light while driving or an inability to start as a reason to stop using the vehicle and call a Kia dealer for guidance. Repair is free at any franchised Kia dealer.
What should I do?
- Check your VIN to confirm your 2017-2018 Kia Niro is included in this recall.
- Contact a franchised Kia dealer to schedule the free Power Relay Assembly inspection.
- Ask the dealer whether your Niro needs the main relay replaced or the full Power Relay Assembly replaced; both repairs address the electrical resistance that can overheat the rear seat above the assembly.
- Bring the recall notice if you have it. If not, reference recall number 18V666 when you call.
- Call Kia customer service at 1-800-333-4542 with questions about scheduling or repair timing.
What happens at the repair
At the dealer, a Kia technician inspects the Power Relay Assembly (PRA) for damage. If the PRA shows no damage, the technician replaces the main relay. If damage is found, the technician replaces the PRA. The recall repair is free, including parts and labor. Kia's General Reimbursement Plan covers repair expenses owners already paid for this condition. Bring receipts or other repair documentation to the Kia service desk, or contact Kia customer service, to start the reimbursement request.
| Reimbursement | Reimbursement available |
|---|
Timeline
| September 25, 2018 | NHTSA published the recall |
|---|---|
| November 16, 2018 | Dealer notification began |
| November 16, 2018 | Dealer notification ended |
| November 23, 2018 | Owner notification mailed |
| November 23, 2018 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 18V666?
Recall 18V666 covers 27,030 2017-2018 Kia Niro hybrid vehicles with a Power Relay Assembly defect. Poor contact inside the main relay can increase electrical resistance, overheat the rear seat area above the assembly, and increase fire risk. Kia dealers will inspect and repair it for free.
What should I do if my 2017-2018 Kia Niro is on this recall?
Check your VIN to confirm your specific Niro is included in recall 18V666. If it is, contact a franchised Kia dealer and ask for recall SC168. The dealer will inspect the Power Relay Assembly and replace the main relay or the full assembly at no cost.
Is the recall repair free?
Yes. Kia's recall remedy states that the inspection and needed Power Relay Assembly repair are performed free of charge. Federal recall law also requires the manufacturer to fix the defect at no cost through a franchised Kia dealer.
What is the safety risk?
The safety risk is fire from overheating under the rear seat. The Power Relay Assembly sits below that area, and poor relay contact can raise electrical resistance enough to overheat the seat area above it. The free dealer repair addresses that relay assembly defect.
What if I bought my Kia Niro used?
The free repair still applies. Recall coverage follows the vehicle, not the first owner. Check your VIN to confirm whether your specific 2017-2018 Niro is included, then give the dealer recall number 18V666 or Kia recall SC168 when you schedule service.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/18V666000 |
|---|---|
| Kia customer service | 1-800-333-4542 |
| NHTSA recall # | 18V666 |
| NHTSA recall # (full) | 18V666000 |
Source documents
-
Download Recall Investigation Document (PDF) (PDF) - 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 →