NHTSA (USA)Critical
At a glance
What can fail
The Power Relay Assembly under the rear seat may overheat in certain 2017-2018 Ioniq HEV and PHEV vehicles.
This page covers 9 recalls, 47 owner complaints and EPA fuel economy for the 2017 Hyundai Ioniq.
136 MPGe combined
Midsize Cars
Fuel economy data from fueleconomy.gov (EPA / U.S. Dept. of Energy). Annual cost based on 15,000 mi/yr at 55% city driving and current fuel prices. MPG is U.S. gallons; L/100km converted. Ranges reflect the 2 tested variants for this model year.
For the 2017 Hyundai Ioniq, the complaints center on electrical and powertrain issues. The electrical system draws the most reports, with owners describing sudden loss of power while driving, in several cases the gas engine shutting off unexpectedly, which also knocked out power braking and steering. A recurring element is the lack of warning before these failures: no dashboard lights or alerts before the vehicle became difficult to control. The hybrid propulsion system also generates complaints, including a power relay assembly failure that left at least one owner stranded with no restart possible and a months-long wait for parts. On the powertrain side, owners report engine failures with jerking and smoke, in one case with a confirmed internal engine failure. Transmission slipping in cold weather, particularly in third gear, appears in more than one report as well.
47
Total Complaints
5
Crash-Related
2
Fire-Related
By System
The 2017 Hyundai Ioniq has 9 recalls, with multiple fire and crash risks spread across the hybrid, plug-in hybrid, and electric variants of the vehicle.
Three distinct fire risks affect different powertrains. On hybrid and plug-in hybrid models, the main relay inside the power relay assembly under the rear seat can develop excessive electrical resistance and overheat, potentially igniting the seat above it. On hybrid models, a leaking oil seal in the hydraulic clutch actuator can allow oil to pool near electrical components and cause a short circuit, also raising the risk of an engine compartment fire. These two issues each have prior repair attempts that did not fully resolve the problem.
On the electric vehicle side, two separate concerns exist. The electronic power control unit can have voids in its housing that allow coolant to reach the circuit board, cutting drive power while the vehicle is moving. There is also a condition where the vehicle can continue to accelerate after the driver lifts off the accelerator pedal, which can occur when the car has entered a reduced-power fail-safe mode due to an unstable electrical ground. Both of these issues apply only to electric models.
At a glance
What can fail
The Power Relay Assembly under the rear seat may overheat in certain 2017-2018 Ioniq HEV and PHEV vehicles.
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Complaints are owner-reported and reflect individual experiences, not confirmed defects. They are distinct from recalls. Data sourced from the national vehicle safety complaint database. See trending complaints →
What the fix does
Dealers will inspect and replace the main relay or Power Relay Assembly as needed at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The vehicle may continue accelerating after you release the accelerator pedal when operating in fail-safe mode.
What the fix does
Dealers will update the electric power control unit software and add ground wiring between the drive motor assembly and frame.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A faulty electrical ground connection may cause the vehicle to enter fail-safe mode, reducing acceleration and power. While in fail-safe mode, the vehicle may continue accelerating even after you release the gas pedal.
What the fix does
Dealers will update the Electric Power Control Unit software and repair the ground wiring at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The main relay contacts in the Power Relay Assembly under the rear seat may not connect properly, causing electrical resistance and heat that could lead to fire.
What the fix does
Dealers will inspect the Power Relay Assembly for heat damage. If undamaged, the main relay will be replaced. If damaged, the entire assembly will be replaced.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The Main Relay in the Power Relay Assembly may have loose or corroded electrical connections, causing higher electrical resistance and potential power delivery problems.
What the fix does
Dealers will inspect the Power Relay Assembly for damage. If undamaged, the main relay will be replaced. If damaged, the entire assembly will be replaced.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The hydraulic clutch actuator may have rough edges that damage its oil seal, causing oil to leak into the phase cap area and create an electrical short, risking engine compartment fire.
What the fix does
Dealers will inspect the hydraulic clutch actuator and replace it if necessary.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The hydraulic clutch actuator's inner oil seal can leak, letting oil collect in the cap area and potentially cause an electrical short.
What the fix does
Dealers will check the actuator cap for leaked oil and replace the entire hydraulic clutch actuator assembly if necessary.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The aluminum casing of the Electronic Power Control Unit may have small gaps that let coolant reach the circuit board inside. This could cut engine power while driving, raising crash risk.
What the fix does
Dealers will inspect the Electronic Power Control Unit and replace it if needed.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
A manufacturing defect in the Electronic Power Control Unit allows coolant to contact the circuit board inside the unit.
What the fix does
Dealers will inspect and replace the Electronic Power Control Unit at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
