2015 Hyundai Elantra engine problems

“The vehicle experienced severe, sudden loss of power while driving, leaving the car unable to exceed approximately 40 MPH on public roads and highways. This restriction creates an immediate rear-end collision hazard and severely degrades acceleration under traffic conditions. Diagnostic & Technical History: The vehicle previously triggered Diagnostic Trouble Code (DTC) P1326 (Knock Sensor / Engine Limp Mode). Diagnostic testing at Holler Hyundai under Techline Case #2026040700281 confirmed severe internal mechanical compression failure in Cylinder 4. Cylinder 4 failed dry compression testing and required a wet compression test (oil added to the cylinder) to hold pressure at 151 PSI. Severe internal engine oil pass-through/blow-by from the damaged cylinder has clogged the catalytic converter with baked oil ash, creating extreme exhaust backpressure that physically restricts vehicle speed and throttle response. Holler Hyundai recently replaced the physical knock sensor to clear the active P1326 light, but the underlying internal mechanical engine damage and clogged exhaust remain unaddressed. Corporate & Warranty Refusal: Hyundai Motor America (Executive…”

“I purchased the vehicle from a private party on 8/18/21 with 38,310 miles. Almost immediately after owning the vehicle I noticed the engine oil level was low.. The owner had said she had just got an oil change so I thought maybe the shop just left it low. Then I noticed it low again a month later, and that was the start of my nearly 5 year journey of having the carrying quarts of oil in the trunk of my car because the engine was burning the oil so quickly. Finally on 5/08/26 the car begins to run very poorly, long story short my personal mechanic and Hyundai of Ontario both confirm the engine is bad and needs to be replaced. I understand there is a history of this year of Hyundai engines burning excessive oil. The car currently has 92,362 miles and even though it’s under the 100,000 warranty Hyundai says the warranty is only offered to the original owner. Any help you can provide to determine if Hyundai has any liability related to this issue would be much appreciated.”

“The engine failed on a 2015 Hyundai Elantra with approximately 71,000 miles. The vehicle has an open, unresolved safety recall (Recall 251, NHTSA #23V651000) for an ABS module brake fluid leak that Hyundai has acknowledged but has not provided a remedy for. The vehicle is currently at an independent repair facility and is available for inspection upon request. The vehicle repeatedly shut off without warning while in motion and restarted mid-drive, causing sudden loss of power steering and power brakes while driving. This occurred on multiple occasions and was documented by an independent service center in February 2026. This presents a serious risk of accident, injury, or death to the driver and others on the road. The check engine light was illuminated. The vehicle experienced recurring brake issues requiring multiple repairs over several years, including brake replacement before 2026 and rear rotor, brake pad, and brake line repairs in February 2026. These brake symptoms are consistent with the known ABS module defect covered under open Recall 251. The engine shutoff symptom was first documented in February 2026 and continued until engine failure in May 2026.”

“I am submitting a vehicle safety complaint regarding a vehicle purchased on March 5, 2026. Within days of purchase, the vehicle exhibited multiple safety-related issues despite reportedly passing a Virginia safety inspection on February 27, 2026. The safety concerns identified include: - Driver-side headlight partially inoperable, which resulted in a traffic stop on March 15, 2026 - Front hood not properly secured/latching, creating a risk of opening while driving - No engine oil present upon inspection shortly after purchase - Coolant reservoir completely empty - Check engine light illuminated shortly after purchase Diagnostic testing following the check engine light revealed code P0420 (Catalyst System Efficiency Below Threshold). A mechanic advised that this condition is not a new issue and would have developed over time, indicating that it likely existed prior to the sale of the vehicle. At the time of purchase, the vehicle had an outstanding manufacturer safety recall identified as NHTSA Recall No. 23V651000 (Recall #251), dated April 3, 2024. This recall had not been completed prior to sale and was only addressed on March 24, 2026, after I took the…”

“The contact owns a 2015 Hyundai Elantra. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power several times, with the check engine warning light and low oil warning lights blinking. The vehicle was able to restart; however, the failure persisted. There was an abnormal tapping sound coming from the vehicle. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 160,000.”

“Engine failure consistent with known Hyundai engine defect. Blue smoke, oil consumption, engine knock Mechanic autoscanned codes were P0300, PO301, PO302 Lost half quart of oil in 800 miles Fire risk acknowledged in recall documentation - undriveable car at Hyundai dealer in Salem NH, renting a car now as without any transportation Manufacturer denied repair based solely on VIN despite identical failure”