2019 Hyundai Santa Fe engine problems

“On 03/26/2026, my 2019 Hyundai Santa Fe received Hyundai Service Campaign 9C2 (TSB 26-01-013H-1), which included an Engine Control Module (ECM) software update for Theta II emissions improvement. The vehicle did not have the following drivability problem before this software update. Immediately after the 9C2 update, the vehicle began jerking/bucking slightly at low speeds, most noticeably around 10-20 mph when coasting with no accelerator input or when applying very light throttle. Acceleration response also feels slower than before the update, with noticeable hesitation when the accelerator is pressed. The problem is most noticeable during the beginning of a drive when the vehicle is cold. After driving for some time and the vehicle warms up, the symptoms improve, although the change in drivability remains noticeable compared with operation before the update. There have been no warning lights or warning messages associated with the problem. The issue began immediately following the ECM software update. The vehicle has not yet been returned to the dealer for diagnosis or confirmation and is available for inspection. I am concerned about the safety implications…”

“The vehicle experienced a sudden, intermittent engine stall while driving, specifically when slowing down or coasting to a stop in live traffic. When the engine dies, the vehicle immediately loses engine power, power steering, and power braking assist, creating an extreme safety hazard. After stalling, the vehicle refuses to restart for several minutes. An authorized Hyundai dealership previously replaced the high-pressure fuel pump under warranty to address this issue, but the dangerous stalling has persisted over the last 2,000 miles. The vehicle continues to randomly shut off without throwing a permanent check engine light or diagnostic trouble code, and the manufacturer has failed to correct this critical safety defect.”

“The car started having problems immediately after replacement with a new battery. The issue with the ISG (Idle Stop and GO System) started appearing. When the Auto Stop Indicator turns green, the car stalls which puts my life at risk. I have spoken to a number of mechanics and I am not getting a satisfactory answer on how to fix this problem.. One mechanic told me it was the starter which turned out not to be true. I have also spoken with a number of other mechanics and they are clueless on how this problem can be remedied. And the Hyundai dealter wanted 275 just to look at it but with no guarentee. The whole issue is putting my life and other motorists at risk.”

“2019 Santa Fe with 80,000 miles showed signs of excessive oil consumption. Service was scheduled with licensed Hyundai franchise service center. Known oil consumption issues on Theta II engines for that year. Testing requires 3 steps. First step is to change the oil and document levels. Engine is tested for 1000 miles then returned to service center. After 1000 miles, service center reports 2.5 qts of oil per 1000 miles. Hyundai corporate was contacted where they approved warranty work for the vehicle. Step two requires Combustion Chamber Cleaning. During this portion of the work, service center calls about fire that took place immediately after a test drive. Dealership states engine and components destroyed.”

“Update Re: ODI Complaint Number: 11759237 Subsequent Actions and Manufacturer Refusal to Remediate Safety Defect: ​Following the [XXX], acute safety incident—where the vehicle lost motive power and entered severe limp mode on [XXX] immediately upon release from Sheehy Hyundai of Chantilly—the vehicle remained in dealer custody for 11 days (August 20–August 31, 2026). ​Failure to Diagnose Core Defect: Despite recurring total power loss, active diagnostic trouble code P00AF00 (Turbocharger Boost Control Module Performance), and four consecutive turbocharger destructions within 20,000 miles, the authorized dealership refused to conduct internal engine diagnostics, drop the oil pan, inspect the oil filter, or perform borescope checks. ​Physical Contamination Documented: On August 29, 2026, an on-site physical inspection confirmed sparkling metallic particulate suspended in the engine oil on the dipstick and substantial oil blow-by/intrusion into the turbocharger air intake line. ​Formal Denial of Safety/Warranty Coverage: On August 31, 2026, dealership management and Hyundai Motor America (Consumer Affairs Case #[XXX]) formally denied warranty assistance and…”

“My vehicle recently received the Hyundai 9c2 emissions upgrade they required and since then the vehicle has had predictable acceleration issues for the first several minutes after the vehicle. While trying to slowly accelerate the vehicle with unpredictably lurch forward. Many people have been reporting this.”