2015–2019 Hyundai Sonata — common problems & known faults

The Sonata is spacious and well-equipped value, but the Theta II engine family's failure risk is the single most important check.

Compiled & reviewed by the VehicleFaults Research Team · last reviewed July 2026

Known faults to check

EngineCritical

Theta II 2.0T/2.4L engine failure (bearing/knock) — subject to recalls and warranty extensions.

Typically appears: 60,000+ miles
What to inspect: Listen for a knock, check for the knock-sensor recall completion, and confirm any engine replacement.

EngineHigh

Excessive oil consumption.

Typically appears: 70,000+ miles
What to inspect: Check oil level and top-up history.

ElectricalLow

Infotainment and sensor glitches.

Typically appears: Any
What to inspect: Test the screen and driver-assist features.

SteeringMedium

Electric power steering faults.

Typically appears: 80,000+ miles
What to inspect: Confirm steering is consistent with no warning lights.

Inspecting a Hyundai Sonata?

Generate a full, tickable pre-purchase checklist tailored to this exact vehicle — add photos and notes as you inspect.

Generate a free checklist

Frequently asked questions

Are Hyundai Sonata engine problems real?

Yes — the Theta II engines have a well-documented failure history with recalls; verify the knock-sensor update and any engine replacement.

Is the Sonata a good used buy?

It offers strong value, but only with confirmed recall completion and clean oil-consumption history.

What's the knock-sensor recall?

Hyundai added a knock-sensor detection system to catch bearing wear early — confirm it was installed.

Sources & further reading

Faults are compiled from documented recalls, technical bulletins, owner reports and mechanic sources, then reviewed for accuracy. This is guidance only · not a substitute for a professional inspection.

Hyundai Elantra