2011 Hyundai Sonata: sudden loss of power

Filed Aug 10, 2026 · Steering · WI

Intermittent and sudden loss of power steering nearly caused an accident for both of sons when each one was driving on two separate occasions this past week. "EPS" and traction control warning lights both illuminate on the dash when steering goes out. Sometimes the codes will clear themselves out after restarting the vehicle, but not always. Had it inspected by an independent service center and they cleared out the codes with their scanner. Steering worked fine for a few days afterwards, but then suddenly lost power steering again yesterday. It is very dangerous to drive and it is very unpredictable. I see that there was a recall for this issue for certain manufacture dates for 2011 Hyundai Sonata, but mine was not part of the recall. I believe that it should be part of that recall before someone dies or is injured.

Filed Mar 25, 2026 · Brakes · 80,000 miles · AR

The contact owns a 2011 Hyundai Sonata. While driving at an undisclosed speed, the vehicle lost power, an alarm sounded for the braking system, and the vehicle went into LIMP Mode and the vehicle failed to exceed 15 MPH. After originally paying out-of-pocket for an ABS module at the dealer and was informed that the engine needed to be repaired and the brakes needed to be replaced. The vehicle was towed to the residence where an independent mechanic repaired the vehicle. There was a recall for the ABS module and the contact returned to the dealer, and the dealer confirmed that the independent mechanic had correctly installed the part. The dealer performed the official recall repair and refused to reimburse the contact for the previous expenses. Three months later, the braking system failed again. The contact stated that the vehicle temporarily returned to normal after a restart, but the failure worsened and required a return trip to the dealer for another repair. In January 2026, the failure recurred for a third time with a loud squealing sound. The dealer was not notified of the third failure. The vehicle was repaired. The manufacturer was notified of the failure. The failure mileage was 80,000.

Filed Jan 26, 2026 · Engine · NY

My Hyundai Sonata has encounter two failing cylinders (compression loss) due to scoring. When driving in the highway I got engine shudder and loss of power (speed) that could have put me in dangerous driving condition, accident or other. These GDI engines are notorious for poor oil circulation due to faulty designed piston rings. Hyundai has long history with these poorly manufactured engines and class action lawsuits. I notified Hyundai but they are not willing to remedy the situation. I have worked with local dealership Miller Hyundai, as well as corporate. All I get are excuses and that I’m not covered. These engines are completely problematic with oil consumption and oil blow by, causing seizing, rod bearing failure, carbon buildup, cylinder damage, etc. The info on the internet over customers and these GDI engines is overwhelming. Oil related Fires are another issue as well. Hyundai needs more accountability than the class action for rod baring failures. Because of the damage to my pistons, I could have gotten in accident with loss of power on highway…full due to poor piston rings, damage from improper oil flow and near complete engine failure.

Filed Jan 9, 2026 · Engine · MO

I am reporting a safety-related engine failure involving my 2011 Hyundai Sonata 2.0T. In November 2025, at approximately 90,000 miles, the vehicle experienced a sudden engine failure while driving, including loss of power and abnormal engine noise. This created an unsafe driving condition and required the vehicle to be removed from service. Component/System Involved: The engine (Theta II 2.0T) suffered a catastrophic internal failure. The engine and internal components remain available for inspection upon request. Safety Risk: The sudden loss of engine power reduced my ability to maintain speed and maneuver in traffic, posing a safety risk to myself and other motorists. Confirmation and Inspection: The failure was confirmed by an authorized Hyundai dealership, which inspected the vehicle and documented the internal valve train condition through photographs. Hyundai Motor America reviewed the claim and issued a written denial. No independent third-party technical inspection was performed. Prior Symptoms: Before the failure, the vehicle had a history of excessive oil consumption requiring frequent monitoring and oil addition despite regular maintenance. Abnormal engine noise was present for approximately one minute before failure. No warning lights adequately predicted the sudden failure. Additional Context: This vehicle is equipped with a Theta II engine, which has been the subject of prior recalls and settlements related to internal engine defects. Hyundai denied warranty coverage alleging “exceptional maintenance neglect”; however, inspection photos show a well maintained valve train with no sludge or oil flow obstruction, only light surface varnish consistent with normal engine aging. I am concerned this failure represents a continuation of a known Theta II engine defect (confirmed by Hyundai technician who performed inspection with OBD code P1326 followed by engine failure) and poses a serious safety risk due to sudden loss of engine power while driving.

Filed Nov 19, 2025 · Brakes, Electrical · VA

The vehicle experiences a recurring defect where the brake light turns on suddenly and the engine shuts off while driving. The failure appears related to the braking system (brake switch circuit), electrical system (CAN-bus/ECU communication), and engine control (shutdown/stall). The system remains installed and is available for inspection upon request. The shutdown poses a serious safety risk, including possible rear-end collision or loss of power in traffic. The problem has occurred multiple times. The dealership inspected the vehicle briefly but failed to diagnose or document the defect and returned the vehicle within hours, stating “it shouldn’t be a problem,” even though the issue continues. Hyundai has refused to provide recall documentation or authorize a re-inspection. The only warnings prior to shutoff are the sudden activation of the brake warning light just before the engine cuts off.

Filed Nov 15, 2025 · Engine · CA

While driving home from work after 7 PM on the 215 NB freeway, the oil warning light suddenly illuminated, and the vehicle immediately lost engine power. Within seconds, the engine shut off completely, leaving me unable to accelerate or safely maneuver. I was forced to coast across lanes with no power, creating a significant risk of collision and nearly resulting in a rear-end accident. After the incident, I performed a crankshaft rotation test, which the engine failed, confirming that the crankshaft would not turn. I also verified that the timing chain remained intact. The vehicle has since been inspected by Hyundai technicians, who confirmed the engine failure under Service Campaign 953. Hyundai further communicated via email that my vehicle is eligible under the TXXI Theta Engine Settlement Agreement and expressed a willingness to discuss my recent engine concerns and the details of the settlement.

Filed Sep 24, 2025 · Engine · TX

I own a 2011 Hyundai Sonata with a 2.0 turbocharged engine. The engine failed/presents issues such as loss of power, rattling, oil consumption, and smoking, which resulted in my engine seizing up. This creates a serious safety risk while driving, to now my car no longer operates. I checked the federal safety agency’s recall database and found no open recalls for my VIN regarding engine replacement, but I believe this engine defect should be investigated for a recall.

Filed Sep 17, 2025 · Fuel system · CA

1. The car began to randomly stall and stop running. This happened while driving and it was extremely dangerous. Typically, the engine would restart after at least waiting 15 minutes. Any attempt to start the car before that time would fail. 2. When the stalls happened, the car acted as if it had run out of gas. The engine would simply stop running WITHOUT WARNING, at intersections, on city streets, and on the freeway at high speed. It did not matter how full the gas tank was. 3. My brother and I diagnosed the problem as intermittent loss of fuel pressure. 4. My brother and I replaced the FACTORY fuel pump, and to hour horror, when we unplugged the electrical connection/plug, one of the pins from the fuel pump came out with the plug/connector. 5. We inspected the fuel pump and discovered that parts of the electrical plug INSIDE THE FUEL TANK had become burned and melted. See Image SANY0135.JPG === This is a SAFETY DEFECT - either the internal fuel pump electrical connections were faulty from the factory or the problem developed over time. There have been other recalls for this model of car for random engine stalls but this is a NEW and DIFFERENT cause. A dealer with a relatively inexpensive Infrared camera could likely spot this problem with minimal vehicle disassembly. There was clearly a LOT of heat concentrated in the area of the electrical connection to the fuel pump. We hope this report triggers a recall and prevents extremely dangerous random loss of engine power events, fires, or worse. Please recall all the vehicles that used that fuel pump for inspection before there is a disaster.

Filed Aug 28, 2025 · Electrical, Engine · IL

2011 Hyundai Sonata had a Theta ii engine replaced in September 2024 after engine failure. Hyundai paid for the engine through the extended warranty on the theta engines. Check engine light is still illuminated after new engine and after multiple visits to the dealership, they say the wiring harness is bad. Contacted Hyundai Corporate who said they will not pay for anymore warranty repairs, even though the wiring harness was damaged from the bad engine or during the replacement. From my understanding, it is dangerous to drive a car with a bad wiring harness due to fire risk, loss of power, or loss of safety components.

Filed Aug 21, 2025 · Engine · CA

While driving our 2011 Hyundai Sonata on [XXX], my fiancée and I experienced sudden engine failure on [XXX]. The car suddenly lost power and began vibrating violently, then stalled completely and would not restart. We had to pull over in a dangerous area with no power and limited shoulder space, creating a serious safety hazard. A relative had previously scanned the vehicle and retrieved a P1326 knock sensor code, indicating a potential engine bearing issue. He cleared the code temporarily in an attempt to drive the vehicle again. However, when it failed on the freeway, we were forced to tow the vehicle twice—first to our home and then to Anaheim Hyundai for diagnosis. Hyundai later denied warranty assistance, claiming "exceptional maintenance neglect" despite the fact that we provided all available oil change records since our 2017 purchase. We were not the original owners, yet were expected to produce records dating back to 2013. No sludge or varnish evidence was cited in the repair order, and the dealer simply claimed a seized engine. We’ve since been denied under both the extended warranty and goodwill policies, even though our engine displayed the same symptoms covered in the Theta II engine class action settlement. This failure was dangerous, left us without transportation, and has caused serious financial and emotional strain. We are reporting this because it reflects a potential ongoing safety risk for other Hyundai owners. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 16, 2025 · Engine, Transmission · TX · crash

While driving on the highway, the motor all of a sudden lost all power and the brakes locked causing a collision. I've never had any problems until then. My car was in tip top shape with no issues until the engine / motor decided to defect. Hyundai she recall this engine issue before someone gets killed

Filed Aug 8, 2025 · Engine · MD

While driving at highway speed, the engine suddenly lost power and the brakes locked. I narrowly avoided a collision. This sudden failure left me unable to safely control the vehicle, placing myself and other motorists in immediate danger. This is not only a mechanical defect but a serious safety hazard that matches the exact conditions described in Hyundai’s prior Theta II engine recalls.