2021 Hyundai Tucson

The vehicle experienced a catalytic converter efficiency failure that was confirmed by an authorized dealership in January 2025. The dealer indicated the catalytic converter required replacement; however, the replacement was not performed, and the vehicle was returned to service with an unresolved emissions defect. Less than one year later, the vehicle developed recurring emissions system failure, loss of power, drivability issues, and repeated warning indicators. The vehicle is currently out of service while additional components, including oxygen sensors and spark plugs, are reported to be affected. The manufacturer is declining to replace the catalytic converter and is attributing the condition to oil consumption despite the prior unresolved emissions failure. The issue has been confirmed by dealership diagnostics and has resulted in prolonged loss of use of the vehicle. This appears to be a continuing engine and exhaust/emissions system defect that was not properly remedied when first identified and may affect safe operation of the vehicle.

The contact owned a 2021 Hyundai Tucson. The contact stated that while driving at 10 MPH, an abnormal clicking sound was coming from under the hood. No warning lights illuminated. In addition, the contact managed to pull over to the shoulder of the road, where white smoke was noticed leaking from under the hood, and the intensity was increasing while the smoke turned black. The local fire department arrived on scene to extinguish the fire. The source of the fire was not identified. It was unknown if a Fire report was filed. A police report was filed. No injuries were sustained, and medical attention was not sought. The vehicle was towed to the contact's residence. The vehicle was deemed a total loss as it was majoily consumed by the fire. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 65,000.

The contact owned a 2021 Hyundai Tucson. The contact stated that immediately after purchasing the certified vehicle, the vehicle went into LIMP Mode while her grandson was driving approximately 65 MPH, and the vehicle decelerated to 7 MPH. The vehicle was towed to the local dealer who diagnosed that the NOX sensor had failed and needed to be replaced. The vehicle was repaired but while leaving the dealer, the failure reoccurred. The vehicle was towed back to the dealer who replaced a second NOX sensor and the catalytic converter. The contact stated that days after retrieving the vehicle, the failure reoccurred, and the vehicle was towed back to the dealer who diagnosed that the NOX sensor had failed for a third time, within several days of owning the vehicle. The vehicle was traded in. The manufacturer was notified of the failure. The failure mileage was 28,944.

I have been adding oil to this engine excessively for more than 3 years..I have had appointments with the dealer where they flat out told me bring it back when the engine fails.i finally got N appointment and was told the engine needed to be replaced.that was 2 weeks ago..they are now denying the claim...have had my car for 2 weeks..no loaner..and decided to deny what they told me

I left my house this am in below zero temperatures. I drove to my daughter's apartment complex 41 miles away. I pulled into her underground parking garage and then heard a loud pop, followed by the rear hatch window imploding into thousands of pieces.

Oil Consumption problems

I am the original owner of this car and in June 2025 I brought my car to Hyundai from noises and they told me it had no oil despite me being up to date with oil changes on the vehicle. They told me they were going to do an oil consumption test and once they did that the engine was denied. 6 months later 3 days after an oil change and no check engine light on, the engine fails while I’m on the side of the highway. This car is not safe. Check engine light was not on and I am always up to date with my cars maintenance.

Oil light comes on between changes at about 1500 miles before needing one, oil does not show on dipstick and have to repeatedly put on in engine. Chance of engine seizing or jumping time.

The issue started just before my vehicle had 60,000 miles on it and only occurred every once and a while but, now it happens more often. When braking at low speeds my car makes a hissing/buzzing noise and the pedal goes soft. We got to a dealership when it had 60,420 miles on it. The dealership had it for two weeks saying they have never experienced anything like this issue before. They even contacted Hyundai Tech to help them. No warning lights ever came on and that was my concern. Finally after two weeks they said my tone ring on my driver's front side was bad and causing a false 0 reading. When I asked why the warning lights didn't come on they told me everything was working like should. Then after I pointed out that they said it was reading a false zero they were like no that must have been a typo its reading four miles under the rest and that's causing the abs system to activate. I'm from Ohio so I know what my abs sounds and feels like when it activates. It's a pulsating feeling not a soft pedal. When my abs truly activates my traction control light comes on. As I stated no lights have ever come on. This issue causes longer stopping times. There hasn't been any accidents because my wife and I try not to drive it. It's going to a third shop to try and figure out the issue. Yes the vehicle is available for inspection.

We were driving and the engine light started flashing and buckling. The vehicle had been properly maintained with oil changes. We have oil changes receipts from our mechanic. Hyundai refuses to cover it under their warranty even though there are documented issues with the make and models of 2021 Hyundai Tuscons.

Engine started making a knocking sound, then the oil light came on followed by the check engine light. Accelerates and decelerates on its own. Was forced to immediately pull over across three lanes on Interstate 95. It’s been over two weeks and I’ve yet to hear if Hyundai is going to cover a replacement engine. However, what happened is exactly what they have listed on their website ️ What to look out for check-engine Check Engine oil-light Engine Oil Pressure A knocking noise from the engine that increases in frequency as the engine rpm increases. Reduced power and/or hesitation and vibration. Illumination of the “check engine” light in the instrument cluster. Illumination of the “engine oil pressure” warning lamp.