The loudest Sonata year in our data, and it is almost entirely one engine — get the bearing coverage in writing.

The 2017 Sonata Hybrid is covered by recall 21V727, which also covers the 2017 Tucson: the connecting rod bearings may wear prematurely and damage the engine, and a damaged engine raises the risk of a fire or a stall. Dealers inspect the engine, replace it free if bearing damage is found, and install the knock-sensor software. This recall grew out of a formal NHTSA investigation. It is the strongest protection available on any 2017 Sonata — and it exists only on the hybrid. Confirm 21V727 shows complete by VIN; an unverified one is a gamble on the most expensive part of the car.

The 2017 Sonata Plug-In has its own file, and it is not the gas car's. Nearly every complaint follows one pattern: a "Check Hybrid System, turn off engine" warning and a sudden loss of propulsion, often at highway speed. Owners are told the high-voltage battery needs replacing, then wait — one reports over a year without a battery, another fifteen months. Two things make this worse. The plug-in was left out of recall 21V727, and an owner whose engine developed a hole in the block at 76,000 miles was told so directly by a dealer. And one owner reports a steering assist motor failing, with the steering locking up until the car was restarted. If you are looking at a 2017 plug-in, ask for the battery's service history first and treat a pending battery claim as a walk-away until you know the part is actually available.

Recall 21V619 covers 2017 to 2018 Sonata and 2016 to 2018 Sonata Hybrid: the trunk latch can be damaged so that the trunk will not open from the inside, which fails the federal internal-trunk-release standard. The fix is a free latch-base replacement. A federal complaint on this generation makes the point concretely — one owner reports the trunk failing to open by any means, with the emergency release not working either. Quick, free, and worth closing.

Recall 16V956 covers 2017 Sonatas built between late May and mid-September 2016: the end seal on the driver's frontal airbag inflator may not have been installed correctly, so the airbag may inflate less than it should in a crash. Free module replacement. Recall 21V749 is a Smart Junction Box software fault that can flash the turn signal in the opposite direction from the one you chose — also free, and it covers the hybrid and plug-in as well as the gas car. Run both against the VIN.

Several 2017 owners report the car turning hesitant and rough at low revs after a dealer visit, with no fix offered. Hyundai's own bulletins explain it. Service Campaign 9C2 reflashes the engine computer on Theta II cars because the California Air Resources Board found them exceeding emissions standards, and Hyundai's follow-up bulletin states that afterwards cars "may exhibit a brief hesitation or rough shifting condition during cold start operation," expected only within roughly the first one to three minutes after start while the catalytic converter warms up. If a 2017 hesitates cold and cleans up after a couple of minutes, that is the software working as designed. Hesitation once warm is a different problem.

Two secondary clusters. A community mechanic channel describes the steering coupler on 2015 to 2018 cars disintegrating over time and leaving play in the wheel, and the federal file carries several 2017 steering complaints including a momentary lock-up. Have a shop check the steering column coupler and listen for a whine or clunk from the column on the test drive. Separately, the 1.6-litre turbo trim pairs with a seven-speed dual-clutch transmission — a computer-operated manual — and the independent mechanic in our sources is unequivocal: don't buy one, the dual clutches in these are "absolutely terrible," and there was often nothing he could do about it. Hyundai issued engine- and transmission-software updates for shift quality on 2015 to 2017 cars. The 2.4 with the conventional six-speed automatic is the easier car; the same mechanic calls that gearbox tried, true and trouble-free.

A Hyundai bulletin covering 2015 to 2019 Sonatas describes an internally leaking fuel pump filter housing causing reduced engine power, a crank-but-no-start condition, or diagnostic code P1233. It is a real, documented part failure rather than an owner theory, and it is worth naming because reduced power and no-start are also symptoms of the far more expensive bearing problem. If the car has a history of intermittent power loss, this is one of the cheaper explanations to rule out first.

Two programmes to know about, neither a safety recall. Hyundai's bulletins describe Campaigns 993, P32 and 9A5 — anti-theft software with window decals, a steering-wheel lock, and a reinforced ignition-cylinder protector — offered because of thefts of 2011 to 2022 Hyundai vehicles built without an engine immobilizer, targeted through social media. Every Sonata bulletin carrying those campaigns lists model years 2011 to 2019, so a 2017 is in the population; a separate class settlement covers the same allegation. Ask whether the 993 software was applied. Separately, Hyundai extended the paint warranty on cars with factory white paint that peels or bubbles on the metal panels, covering 2015 to 2019 Sonatas — the published summary does not state the term, so verify it in the bulletin PDF before paying for bodywork.