2021 Hyundai Ioniq

VEHICLE SAFETY HAZARD: ACTIVE HIGH-VOLTAGE ISOLATION FAULT (DTC P0AA6) WITH DECEPTIVE DEALER/MANUFACTURER BYPASS & CONCEALMENT. On April 15, 2026, the dealer scanned my 2021 Ioniq EV and uncovered DTC P0AA6 (Hybrid/EV Battery Voltage System Isolation Fault), which denotes a catastrophic high-voltage leak into the chassis. This is a severe safety hazard posing immediate risks of fatal electrocution to occupants, EV battery thermal runaway (fire), or sudden total loss of propulsion at highway speeds. Instead of grounding this dangerous vehicle, the dealership concealed the diagnostic code, withheld the physical invoice, and released the vehicle back to me on April 28, falsely claiming it was "fixed to 100%." They forced me to drive an actively compromised high-voltage system. On May 7, the defect immediately returned while driving. I confronted the dealer on May 8 for merely resetting the car's computer to bypass the safety warning, which is an extremely dangerous fire hazard. The manufacturer has refused to replace the defective EV battery under warranty, or provide alternative transportation. This vehicle has now been grounded and decaying in an open lot for over 95 days. This is a severe systemic manufacturing defect and fraudulent maintenance practice that requires an immediate NHTSA safety investigation.

Reported

Jul 2026

Incident date

May 2026

Mileage

Not provided

Outcome flags

None reported

Installing a car seat and the belt buckle failed. The plastic part split and no longer holds the belt together. This was under regular pressure with standard leverage that the car seat design calls for. Nothing was ever on top of the buckle and it is not damaged in any other way at all other than the failure. They refused to replace it via warranty.

Reported

May 2026

Incident date

Feb 2026

Mileage

Not provided

Outcome flags

None reported

Auto Hold/EPB lights come one while driving. Deactivates cruise control of on. Turns off auto hold. Ongoing issue with many reports but no recall or dealership knowledge. Ongoing issue since purchase.

Reported

Jul 2025

Incident date

Jun 2024

Mileage

Not provided

Outcome flags

None reported

The "Auto Hold" feature on my Hyundai Ioniq malfunctioned, displaying a dashboard warning: "AUTO HOLD conditions not met. Press brake pedal." This message randomly appears while driving or stopping, and it deactivates the Auto Hold and Electronic Parking Brake (EPB) functions. In some cases, the car rolls after stopping because the system fails to hold the vehicle. This issue compromises vehicle safety, especially on inclines or during stop-and-go traffic. It puts me, passengers, and other drivers at risk. The problem has occurred multiple times and is unpredictable. It appears to be linked to a faulty brake switch or sensor, as noted in Hyundai’s TSB 23-BR-001H. I discovered this issue is affecting many other Hyundai Ioniq owners, as seen in this discussion: [XXX] The dealer has not yet inspected the vehicle, but the symptoms match the TSB. No accident has occurred, but the safety risk is serious due to brake failure behavior. There were no visible warning lights before the issue started, just the "Auto Hold" message when the failure happens. I bought the car from a used car dealer when it had 39,000 miles. Now it has around 74,000 miles. I’m not sure if it’s still under warranty. I haven’t taken it to the dealer yet, but the symptoms match exactly what other people are reporting online. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Reported

Jul 2025

Incident date

May 2025

Mileage

Not provided

Outcome flags

None reported

The contact owns a 2021 Hyundai Ioniq Hybrid. The contact stated that upon depressing the accelerator pedal, there was an abnormal ratting sound coming from the vehicle, and the vehicle failed to accelerate as needed. The contact stated that the check engine and oil warning lights were illuminated on the instrument panel. The vehicle was taken to a dealer where the vehicle was diagnosed with connecting rod bearing failure. The contact was then provided an estimate for an engine replacement. The manufacturer was also notified of the failure and the contact was provided a case number. The vehicle remained in the possession of the dealer and was not yet repaired. The failure mileage was 73,020.

Reported

May 2025

Incident date

May 2025

Mileage

Not provided

Outcome flags

None reported

Auto brake fault has been a constant issue with this 2021 Hyundai Ioniq Hybrid. This causes lots of system functions to stop working (adaptive crusice control, lane keeping assistant, etc.) The dealer originally replaced the wiring harness, but it came back again and again with the same issue. They finally figured out that replacing the rear calipers seemed to make it stop. They have done that twice and this past weekend the fault warning appeared again. So, for the 4th time, we will be taking the car back in so this error goes away. For additional details, I will give you the most recent time, but note that the other 3 times all happened with in the first 1-3 years of ownership.

Reported

Oct 2024

Incident date

Oct 2024

Mileage

Not provided

Outcome flags

None reported

On a recurring basis, the warning lights come on for”AUTO HOLD” and “EPB” or emergency parking brake. Car continually beeps and gives warning until car is reset. During this time, the cruise control will turn off, causing safety issues during travel. Also, the other safety features seem to stop working during the time this warning is activated. Emergency stop, et cetera. Only activated when vehicle is operating under highway mph. Typically local roads with stops/starts trigger this issue. Mechanics have no idea what is wrong with vehicle warning. I see online that this is a common issues with Hyundai Ioniq. A possible recall is needed to investigate/fix this issue as local dealerships arent aware of a solution.

Reported

May 2024

Incident date

May 2024

Mileage

Not provided

Outcome flags

None reported

The contact owns a 2021 Hyundai Ioniq Hybrid. The contact stated that while driving at various highway speeds, the electronic parking brake and auto hold indicator lights erroneously activated. The cause of the failure was not yet determined. The local dealer was notified of the failure, but no assistance was offered. The manufacturer was not yet contacted. The VIN was not available. The failure mileage was 16,000.

Reported

Aug 2023

Incident date

Jan 2023

Mileage

Not provided

Outcome flags

None reported

I’m driving with cruise control on the highway at 65 and all of a sudden it shuts off. The check cruise system light comes on along with a triangle with an exclamation point in the middle of it in the lower left side of dashboard and the letters EPB lights up on the lower right side of dashboard.

Reported

Aug 2023

Incident date

Jul 2023

Mileage

Not provided

Outcome flags

None reported

The contact owns a 2021 Hyundai Ioniq EV. The contact stated that on several occasions the vehicle would not start or could not be restarted after being turned off. The vehicle was towed to the local dealer who was unable to determine the exact cause of the failure but indicated that the failure was related to the 12V battery system. The vehicle was not yet repaired. The manufacturer and local dealer were notified of the failure. The failure mileage was 22,000.

Reported

Jun 2023

Incident date

Mar 2023

Mileage

Not provided

Outcome flags

None reported

The contact owns a 2021 Hyundai Ioniq Hybrid. The contact stated while driving at an undisclosed speed, the electronic parking brake warning light, the auto-hold feature warning light, and other unknown warning lights were illuminated. The contact veered to the side of the road. The contact turned off and restarted the vehicle; however, the failure persisted. The contact was able to continue driving. The vehicle was taken to the local dealer where it was diagnosed that the brake caliper had failed and needed to be replaced; however, parts were not available. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 19,000.

Reported

Sep 2022

Incident date

Aug 2022

Mileage

Not provided

Outcome flags

None reported

When driving down the highway the cruise control will turn off and it is during sunny days and has happened many times. The check lane following assist LFA system notice comes on, the smart cruise ctrl conditions not met notice come on, the check smart cruise control system notice comes on, auto hold, EPB and two triangles appear. Happened 4/2, 4/20, 6/9, 6/17. I have told service about it but they say there isn’t any problem.

Reported

Aug 2022

Incident date

Jun 2022

Mileage

Not provided

Outcome flags

None reported

The Apple car play system quits when you are using maps.

Reported

Aug 2022

Incident date

Aug 2022

Mileage

Not provided

Outcome flags

None reported

The backup mirror remained on while driving down the road.

Reported

Aug 2022

Incident date

Jun 2022

Mileage

Not provided

Outcome flags

None reported

Owner of 2021 Hyundai Hybrid Ioniq. Auto hold and EPB (electronic parking brake) malfunction lights come on randomly. After inspection at dealership electronic brake control module needs replacing, not communicating with car Module is currently on backorder and may take six weeks for part to come in. Dealership's service dept. fully understood what repair is needed and is taking care of the problem. We were strongly advised NOT TO DRIVE the car until repaired. Vehicle could possibly auto stop going at high speeds. Dealership provided a rental car until the repair is made. This is a great dealership , one that has concern for the consumer's safety over their bottom line. We'll know in about six weeks if replacing the module fixes the problem.

Reported

Aug 2022

Incident date

Aug 2022

Mileage

Not provided

Outcome flags

None reported

During a highway trip that was bumper to bumper traffic at approximately 15mph, the car suddenly would not accelerate while operating on gasoline (not electric). The engine revs would increase to maximum without movement from the car (as if the car was in neutral). After checking the gear lever to make sure it was still in D, tried to accelerate again and engine rev high without movement. Eventually car came to stop with brakes, and the car could move on electric power (in hybrid mode), pulled over and turned off the car to visually inspect. After not identifying anything, turned on car and operation resumed to normal and would accelerate on gas power.

Reported

Jul 2022

Incident date

Jul 2022

Mileage

Not provided

Outcome flags

None reported

Two different scenarios with this cruise control are problems with this vehicle. When it is raining the system with the cruise control does not work and the shop told me it happens with other vehicles. A warning light appears when this happens. This last time it was not raining and the cruise control quit working and the warning light came on as well as another system warning light. I showed the picture to the guy at the shop and he said after I showed him the picture he knew what to do, he had to reset the system. Yes, it’s available for inspection. When you’re driving in traffic on the highway going 65 and the car slows down for no apparent reason, that is a problem. The vehicle has not been inspected.

Reported

May 2022

Incident date

Apr 2022

Mileage

Not provided

Outcome flags

None reported

The contact leased a 2021 Hyundai Ioniq Electric The contact stated that while the vehicle was parked, he attempted to open the driver’s side door using the key fob; however, the door would not open. The contact contacted Hyundai roadside assistance who assisted him in jumpstarting and recharging the batteries. The contact was still able to drive the vehicle. The contact stated that a couple of days later, the vehicle failed to start after several attempts. The vehicle was towed to the dealer where it was diagnosed that the mechanic switch that applied the emergency brake was not completely closed and kept the electrical circuit for the emergency brake activated causing the two batteries to drain. The vehicle was repaired. The manufacturer was notified of the failure and advised the contact that they would reimburse him for the vehicle rental expenses under the condition that he surrendered his rights to pursue reimbursement for the vehicle repair expenses. The failure mileage was approximately 3,400.

Reported

Feb 2022

Incident date

Dec 2021

Mileage

Not provided

Outcome flags

None reported

The contact owns a 2021 Hyundai Ioniq Hybrid. The contact stated that upon starting the vehicle, the auto-hold warning light would illuminate on the instrument panel. The contact had taken the vehicle to a dealer however, the mechanic was unable to determine the cause of the failure. The contact was informed that he had to pay a diagnostic fee to service the vehicle. The manufacturer was notified of the failure and referred him to another dealer for assistance. The vehicle was not repaired. The failure mileage was approximately 4,000.

Reported

Nov 2021

Incident date

Oct 2021

Mileage

Not provided

Outcome flags

None reported

06/08/21 first day I brought my new car Hyundai Ioniq 2021 model at Hyundai Lincolnwood. After use the car about 2 months, the engine light has been showing up that something wrong about the auto hold and EPB. So I made an appointment for inspect in the next day. 09/21/21 - they were called to let me know that the car had been fixed and it was ready to pick up. So I went to pick up around 3.00p.m. after checked my car and about to leave the dealership, the auto hold engine light was show up again. So I had to take my car back to fix it. After have been waiting my car to fix about 2 months. I haven’t received any updates from them. 10/21/21 - the GM called me. So I went to the talk with him. He said the cost to fix my car about $5,000. I have to pay for in order to fix it because my warranty not cover for the break. I wondered why I have to pay even though it wasn’t my false. I brought this car and used it not over 3 months. Hyundai should take responsibility for the fixing cost not me. So I denied to pay. Then he left and brought me my car key and said my car was outside. Then I went out from the showroom and found out that the car he brought wasn’t mine. The car he brought is white color but mine is grey. So I checked on the white car and found out that the car was show the auto hold engine light with the same as my problem. So I guess I’m not the only one that had this problem even though I asked them earlier that has anyone had the same problem as mine and they said no and insisted that my car was the only one that have this problem. 5 minutes later, the GM came back with my actual car. And I end up the day by got my car back with the auto hold engine light still on. The GM didn’t care about this issue. He didn’t care about customer’s life and seem to care about the circulation more than fixing problem after sale service. Now I still wondering why the factory keep producing the car model even though i found a lot of consumer complaint about it.

Reported

Oct 2021

Incident date

Aug 2021

Mileage

Not provided

Outcome flags

None reported