The 2017 Hyundai Sonata received a mid-cycle refresh but inherits the infamous 2.4L Theta II GDI engine and the related 1.6T/2.0T turbo Theta II variants. Engine failure due to bearing wear is the dominant issue. The KSDS (Knock Sensor Detection System) recall and an extended warranty (10 years/120,000 miles) cover affected engines.
Major engine reliability issue. The 2.4L Theta II GDI and turbo Theta II variants have widespread bearing failures leading to seized engines. Hyundai issued the KSDS recall, an extended warranty (10yr/120K), and class-action settlements. Engine replacement under warranty is common.
Connecting rod bearings fail due to manufacturing defects, causing knocking, oil pressure loss, and seized engines. Hyundai extended powertrain warranty to 10 years/120,000 miles for affected engines and issued the KSDS recall to detect knock early.
View P1326 Diagnosis →Turbo Theta II also affected by bearing failures. Listen for knock, monitor oil pressure.
View P1326 Diagnosis →Knock Sensor Detection System reflash. Tells you early if bearings are failing. ALWAYS verify recall completion before buying.
View P1326 Diagnosis →Even healthy Theta II engines burn oil. Check level monthly.
Run free diagnosis →Steering intermediate shaft can separate. Verify recall completion.
Run free diagnosis →Pretensioner can rupture in collision. Verify recall.
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Avoid unless you can verify the engine is new under warranty replacement, all KSDS recalls completed, and you fully accept the bearing-failure risk. The 10-year/120K powertrain warranty extension provides some protection but does not eliminate inconvenience.
No - the 2017 Sonata inherits the Theta II disaster. Even with extended warranties, ownership risk is high. If you want a Sonata, the 2020+ 8th gen with the new Smartstream engines is a much safer choice.
Expect $400-700/year in routine maintenance, plus high probability of an engine warranty claim or replacement. If outside warranty, engine replacement is $5,000-10,000+. Lifetime non-routine cost: highly variable depending on warranty coverage.
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If your 2017 Sonata is throwing a check engine light, these are the codes most often associated with the problems above. Click any code for full diagnosis steps and typical repair costs.
Yes - the 2.4L Theta II and 2.0T Theta II have widespread bearing failures. Hyundai extended powertrain warranty to 10 years/120,000 miles and issued the KSDS recall.
Knock Sensor Detection System - a software reflash that monitors for knock and triggers a warning before catastrophic failure. Always verify completion on used Sonatas.
Only if engine has been replaced under warranty (with documentation), all recalls are completed, and you accept ongoing risk. Most buyers should look elsewhere.
For affected Theta II engines, Hyundai extended powertrain coverage to 10 years/120,000 miles from the original in-service date.
Both are Theta II variants with bearing failure risk. The 2020+ 8th-gen Sonata uses the much-improved Smartstream 2.5L - that is the safer choice.