We are reporting a suspected thermal runaway incident involving our recently purchased used 2023 Hyundai Ioniq 5 and have significant concerns regarding the vehicle's safety. **Vehicle Information** * Purchased XXX, 36,662 miles * Clean inspection and no accidents per Carfax **Incident Timeline – XXX** Between 6:00 and 6:30 PM, while traveling northbound on [XXX] just past the [XXX] exit in [XXX], the vehicle struck a white piece of road debris that appeared flat, similar to Styrofoam (video available). There was no immediate loss of vehicle function. [XXX] The vehicle was then moved to the driveway for inspection after a low coolant warning appeared. Damage to the underside near the driver's side and observed blue coolant leaking from the area. The coolant reservoir under the hood was empty. Based on online guidance advising against driving a vehicle with a coolant leak, we decided to leave the vehicle parked in our garage overnight and arrange a flatbed tow to a Hyundai dealership the following day. The garage door was closed, and the vehicle was **not charging**. At approximately 8:10 PM, a burning smell was detected inside the home. Upon opening the door between the house and garage, smoke was observed. The family immediately evacuated, and XXX was called at 8:12 PM. The fire department arrived at approximately 8:18 PM and found the garage filled with smoke. At 8:30 PM, firefighters removed the vehicle from the garage. At 8:35 PM, flames were observed beneath the vehicle. Firefighters applied water directly to the fire until 11:00 PM, after which the vehicle was removed. [XXX] [XXX] [XXX] Manufacturer was contacted; denies any liability due to debris. However, we believe inadequate safety design contributed, including soft protection shield and poor location of coolant. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Hyundai Ioniq 5 overheating problems
42 of the 1,354 owner complaints about the Hyundai Ioniq 5 describe engine overheating, most of them for the 2023 model year.
- owner complaints
- 42
- worst model year
- 2023
By model year
Often reported together
What owners say
Car charged as scheduled overnight 3/28/26 but was dead the morning of 3/29/26 and when it was jumped gave error "Battery overheated, please stop and exit vehicle" and "check electrical system" - vehicle has been in shop for 16 days, no diagnosis except that it "probably" needs a HV battery.
Received the following warning while driving my 2025 Hyundai Ioniq 5 SEL on the highway on X-mas night: "Battery Overheated! Pull over safely and leave the vehicle." Within a few miles, was able to pull over at the nearest exit and park the car off the highway. Then turned the car back on to see if the error message was still present and drove another mile, only to get the same error message. As soon as I pulled into an empty parking lot, the car lost power and was not functioning (ie unable to accelerate). I received a further "Battery Management System" error in the Vehicle Diagnostics dashboard. It was raining outside so was very uneasy that I was prompted to leave the vehicle with two young kids in the backseat. We took an Uber home which was a couple miles away from the parking lot where my stranded car was located. I had the vehicle towed to Hyundai San Leandro on 12/26/25, it was inspected on 12/30/25, and was notified by the dealership service center on 1/2/26 that the ICCU may need to be replaced to resolve the issue. They did not confirm whether they were able to reproduce the issue but I see two DTC error messages in my Hyundai app (DTC P1B9700 and DTC POA9B11). It was indicated that an ICCU was ordered which should arrive by 1/8-1/9 (3-4 days from 1/2) . If swapping in a new ICCU doesn't resolve the issue, then it was indicated that I may need a new BMS module. I was given the option to get a rental car from Enterprise (as early as the weekend of 1/3-1/4) and get reimbursed later or a loaner vehicle could be provided (if available) by the dealership sometime during the week of 1/5.
I purchased my Hyundai Ioniq 5 on [XXX]. Since then, I have experienced repeated and dangerous failures of the air-conditioning system, which Hyundai and the selling dealership have failed to properly diagnose or repair. On [XXX], while driving, I heard a very loud banging noise coming from the front passenger side of the vehicle. Immediately afterward, the air-conditioning system completely shut down and stopped producing cold air. Before the extreme Arizona heat began, I repeatedly asked Hyundai on Bell Road in Glendale to properly diagnose the A/C system due to ongoing concerns. Despite the vehicle being under warranty, the technician told me I would have to pay a diagnostic fee before they would evaluate the A/C. As a result, the underlying problem was not properly diagnosed or repaired. On [XXX], the exact same failure occurred again the same loud banging noise followed by a complete loss of air conditioning. The vehicle was taken to Hyundai on Bell Road in Glendale a total of four (4) times, spending 33 days out of service for the same issue. Despite this, the dealership failed to repair the vehicle. On several visits, the car was simply parked, and the dealer later claimed it had been “fixed” one time, even though the problem continued. This defect created a serious safety hazard. During one incident, while driving the vehicle in extreme heat to the dealership for repair, the interior temperature became dangerously high. My phone overheated and shut down, and I nearly passed out while driving. Hyundai Corporate has been unresponsive and dismissive. Rather than addressing the repeated failures and safety risks, I was referred to Lemon Law, where my claim was denied, despite the extensive repair history and time out of service. Instead of repairing the defect or taking responsibility, both the dealership and Hyundai Corporate pressured me to trade in the vehicle and move on, without resolving the underlying problem. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
On October 10, 2025, while driving the car, a turtle suddenly popped up in place of the speedometer. The car's power and speed was drastically reduced. There was a car behind me that started tailgating me and I could not go any faster than about 15 mph. I was able to make it home. Later that night, I tried to charge the car and it started to overheat. The ICCU recall need to be extended to 2025 models. Ours has been replaced, as well as the PCM and many other parts. Our car still sits at the Hyundai service center because they cannot figure out why the car won't charge.
Was driving for 12 miles, at a stop light. Light turns green, I accelerate, loud collision warning goes off and warning “battery overheated! Pull over safely and leave the vehicle”. Could not pull over safely because the car immediately ceased and locked up, car behind me nearly rear ended me and swerved to avoid. Is this another ICCU unit failure? Car towed to dealership (car has 2056 miles in it, it’s practically new) and been there for almost a month now with no repairs done and still diagnosing the problem. This car is unsafe.
The contact owns a 2022 Hyundai Ioniq 5. The contact stated that the electrical charger was overheating, and the 12-volt battery was draining without warning. The contact stated that while charging the vehicle, the contact heard an explosion. The contact stated while driving 20 MPH, the message "Stop Driving Immediately - Return to Dealer"; the check engine warning light illuminated, and the vehicle experienced a loss of automotive power. The contact stated that on one occasion after turning off the vehicle, the battery remained active for 3 days, causing the battery to become drained. The vehicle was taken to a local dealer where the vehicle was diagnosed and the contact was informed that the water pump, the EV battery, the charge point, the inside batteries, the sensors, the navigation system, were faulty and needed to be replaced. The vehicle was repaired; however, the failure persisted. The manufacturer was notified of the failure. The approximate failure mileage was 65,000.
Our all-electric AWD Hyundai Ioniq 5 has an issue where the rear motor electric oil pump (EOP) overheats and ceases to function when the problem occurs, which disables the rear motor and effectively causes the car to become a front-wheel drive vehicle with a "hesitation" in the acceleration. This problem only occurs after a long time of high-speed driving and typically on a warm day (upwards of 70-80 degrees F). When the problem occurs, the rear motor ceases to function at all and only the front motor operates to power the vehicle forward. The acceleration is also impacted, such that when the accelerator is pushed, the car "hesitates" for 1-3 seconds before the front motor takes over the demand for power and "lurches" the car forward in a jerky motion. The symptom will last as long as the car is in an overheated state. However, if you pull the car over and let it rest for a period of time (undetermined), the rear motor will again operate normally until it overheats again. For us, this occurred once on a very hot day traveling approximately 50-60 miles on interstate travelling at speeds over 70 MPH. On another occurrence, it happened after driving the car about 200 miles (stopping for a lunch break in the middle), for about 4 hours. When this problem occurs in other cars equipped with RWD only, they lose all forward power in the car and coast to a stop even when the battery still has a charge. We've taken it to our local dealership for repair on Sept 12, 2024 (McGee Hyundai of Barre, VT) and they claim that there is nothing wrong with the vehicle. After researching the topic, I've determined it is the failing rear EOP must be replaced [XXX] and [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
When charging the car on level 2 charger at 40 amps, the connector where the charger plugs in overheats. Based on updated software the car reacts by turning off the charging, but I am concerned it may not always do that and the connector would overheat and fail. Also the car is not fully charged as it should be. This occurs perhaps 1 out of 2 or 3 charging sessions. Hyundai is aware of this but has chosen not to address the issue beyond shutting off charging, which is not an acceptable response. The local dealer appears to be unaware of the problem. They indicated I would have to pay for them to inspect it and only be reimbursed if the issue is under warranty
Vehicle's charging port appears to be overheating to the point that thermal throttling is occurring when attempting to charge. This issue first occurred in mid-May of 2024. Vehicle charged as normal before then. Vehicle was serviced by dealership for this issue on 05/29/2024. A software update was applied that did not solve the problem. In an attempt to find updates on this problem, I contacted Hyundai Customer Care by phone on 05/30/2024. Hyundai Customer Care agent read a scripted response that was first released to the public in 20203 and advised to wait for an unknown amount of time for an unknown fix which may or may not come to pass. Hyundai Customer Care had no updates more recent than the 2023 release from which the Customer Care agent read. This appears to be a known issue with no actual fix available to the customer and no ETA on when such a fix might be released.
Related recalls
No recalls on record for this model year.
Questions about the Hyundai Ioniq 5 overheating
Which Hyundai Ioniq 5 years have engine overheating problems?
The model years with the most reports are 2023 (20 complaints), 2022 (18 complaints) and 2025 (4 complaints).
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