2011-2020 Sonata Hybrid and Optima Hybrid engine problems

Last reviewed 2026-10-09 · Data: NHTSA, official settlement and manufacturer documents · Independent site, not affiliated with Hyundai, Kia or NHTSA

Short answer

The hybrid versions of these sedans are not in the Theta II GDI settlement that covers the gas Sonata and Optima. They're on the Engine II settlement lists instead: the 2.4L Theta II MPI hybrids (Sonata Hybrid 2011-2015, Optima Hybrid 2011-2016) and the 2.0L Nu GDI hybrids and plug-ins (Sonata 2016-2019, Optima 2017-2020). That's 15 years / 150,000 miles from original retail delivery for connecting-rod bearing damage, with KSDS required first. Several model years also have their own bearing-wear recalls.

Check your VIN to see recalls and which programs list your exact engine.

Which engines and years are involved

2011-2015 Sonata Hybrid, 2.4L Theta II MPI hybrid: Hyundai Engine II. Certain 2011-2013 are in recall 20V-746.
2016-2019 Sonata Hybrid and Plug-In, 2.0L Nu GDI hybrid: Hyundai Engine II. Certain 2016s are in 20V-746 and certain 2017s in 21V-727.
2011-2016 Optima Hybrid, 2.4L Theta II MPI hybrid: Kia Engine II. Certain 2011-2013 are in fire recall 20V-750.
2017-2020 Optima Hybrid and Plug-In, 2.0L Nu GDI hybrid: Kia Engine II. Certain 2017-2018 are in recall 21V-844.

NHTSA files plug-in models under separate names ("Sonata Plug-In", "Optima Plug-In Hybrid"), so the tables below count the regular hybrids only.

What the settlements and recalls say

KSDS (Knock Sensor Detection System) is free dealer software that listens through the knock sensor for the vibration pattern of a worn connecting-rod bearing. If it hears it, it turns on the check-engine light and limits engine power so the car can be driven to a dealer instead of the engine failing on the road. Kia's dealer letter names the trouble code P1326 for this condition.

Hyundai Engine II settlement (In re: Hyundai and Kia Engine Litigation II, C.D. Cal.): the official site says judgment was entered April 26, 2024. It extends the powertrain warranty to 15 years or 150,000 miles from original retail delivery, whichever comes first, for short-block or long-block damage caused by connecting-rod bearing failure.
Condition: the KSDS update must be done at a Hyundai dealer before any covered failure. Vehicles under Hyundai recalls 198 and 209 (NHTSA 20V-746 and 21V-727) are exempt from that requirement, per the site.
Later owners: the site says the extended warranty carries over to later private owners. It is not available to commercial entities such as used-car dealers or auction houses.
Deadlines: cash claims (towing, rental, inconvenience, fire losses, rebates) expired July 8, 2024. The extended warranty itself needs no claim form.
Kia Engine II settlement (In re: Hyundai and Kia Engine Litigation II, C.D. Cal., final approval April 2024): extends the powertrain warranty to 15 years or 150,000 miles from original retail delivery, whichever comes first, for short-block and long-block damage caused by connecting-rod bearing failure, for original and later private owners. The KSDS update has to be done at a Kia dealer first.
Deadlines: cash claims (past repairs, towing, rental, fire losses) closed July 8, 2024. The extended warranty continues and needs no claim form. Kia's settlement site sometimes blocks automated visitors, so if it won't load, ask a Kia dealer to look up your VIN.
Bearing recalls 20V-746, 21V-727 and 21V-844: dealers inspect the engine, replace it if bearing damage is found, and install KSDS.
Fire recall 20V-750: inspect for fuel and oil leaks, test the engine, repair or replace as needed, update KSDS.
Anti-theft: hybrids follow their gas twins' model lists (Sonata 2011-2019, Optima 2011-2020). Only turn-key cars without an immobilizer need it. Check by VIN.

Engine-related recalls

20V-746 · ENGINE
Hyundai Motor America (Hyundai) is recalling certain 2015-2016 Veloster, 2012 Santa Fe, 2011-2013 Sonata Hybrid, and 2016 Sonata Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which over time can result in engine damage.
21V-727 · ENGINE
Hyundai Motor America (Hyundai) is recalling certain 2017 Tucson and Sonata Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which can result in engine damage.
20V-750 · ENGINE
Kia Motors America (Kia) is recalling certain 2012-2013 Sorento, 2012-2015 Forte and Forte Koup, 2011-2013 Optima Hybrid, 2014-2015 Soul, and 2012 Sportage vehicles. An engine compartment fire can occur while driving.
21V-844 · ENGINE
Kia Motors America (Kia) is recalling certain 2017-2018 Optima Hybrid and Optima Plug-In Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which can result in engine damage.

Recall text quoted from NHTSA. Whether a recall is still open on a specific car can only be checked by VIN at NHTSA or the manufacturer.

What owners report to NHTSA

2011-2019 Sonata Hybrid

667 complaints have been filed with NHTSA for the 2011-2019 Sonata Hybrid. 319 of them name an engine component.

Model year	All complaints	Engine complaints	Engine + fire	Typical mileage mentioned (engine)
2011	96	41 (43%)	3	too few (n=7)
2012	154	70 (45%)	5	too few (n=7)
2013	108	41 (38%)	3	too few (n=4)
2014	29	14 (48%)	0	too few (n=1)
2015	54	21 (39%)	2	too few (n=1)
2016	132	75 (57%)	2	too few (n=8)
2017	80	49 (61%)	2	too few (n=6)
2018	9	5 (56%)	0	too few (n=2)
2019	5	3 (60%)	0	too few (n=1)

Source: NHTSA complaints API, pulled 2026-10-09. "Engine complaints" are complaints where the owner picked an ENGINE component (one complaint can list several components). Mileage is the median of mileages owners typed into their complaint text, shown only when at least 10 complaints mention one. Complaints are unverified owner reports, and counts reflect how many owners filed, not how many cars failed.

2011-2020 Optima Hybrid

485 complaints have been filed with NHTSA for the 2011-2020 Optima Hybrid. 242 of them name an engine component.

Model year	All complaints	Engine complaints	Engine + fire	Typical mileage mentioned (engine)
2011	34	19 (56%)	2	too few (n=4)
2012	109	73 (67%)	5	88,000 (n=14)
2013	55	14 (25%)	0	too few (n=1)
2014	31	16 (52%)	1	too few (n=3)
2015	12	5 (42%)	2	too few (n=0)
2016	4	2 (50%)	1	too few (n=1)
2017	26	17 (65%)	0	too few (n=3)
2018	3	3 (100%)	0	too few (n=0)
2019	210	92 (44%)	5	95,000 (n=23)
2020	1	1 (100%)	0	too few (n=1)

Hybrid complaint counts are small, so a few reports move the percentages a lot. The Optima Hybrid 2019 row (210 complaints) is far above its neighbors, which may mean NHTSA's data mixes in complaints about the gas 2019 Optima. Treat that row with caution.

Warning signs to take seriously

Knocking from the engine when the gas engine runs, especially under load.
Flashing check-engine light and limited power after KSDS.
Fuel or oil smell, or smoke from the engine bay.

What to do, step by step

Check your VIN at NHTSA and at Hyundai or Kia for the bearing and fire recalls.
Ask the dealer to confirm KSDS is on file. Engine II requires it before a failure (Hyundai cars under 20V-746 or 21V-727 are exempt from that requirement).
With symptoms, call the dealer's service department with the VIN before paying for diagnosis, and say "Engine II settlement" by name.

Dealer insider note

Hybrids are handled differently from the gas cars. The guide above says the Sonata and Optima hybrids are not in the Theta II GDI settlement. They are on the Engine II lists: 15 years or 150,000 miles from original retail delivery for connecting-rod bearing damage, with KSDS required first. Hyundai cars under recalls 20V-746 or 21V-727 are exempt from the KSDS requirement. Several model years also have their own bearing-wear recalls.

Ask the advisor to confirm your engine from the VIN, because the 2.4L Theta II MPI and the 2.0L Nu GDI hybrids are different. Say "Engine II settlement" by name.

At the desk: bring the VIN and say: "Please check for open campaigns and recalls, and tell me whether KSDS is on file." Ask for the repair order to show the campaign number and the KSDS date. If you have symptoms, call the service department with the VIN before paying for any diagnosis, and ask whether a diagnostic fee applies if the car is covered.

A used hybrid buyer should ask about KSDS before anything else: has it been done, and is there a record? Ask for recall history, engine replacement paperwork, and maintenance records. Ask how the mileage and age limits apply to this car.

Until the campaign check is done, do not sign a customer-pay repair order or anything blank, and do not approve a paid engine repair or diagnostic fee without asking whether a campaign or settlement applies to your VIN.

If the shop stalls or says no, call the manufacturer's customer-care line (number is in your owner's manual). Give the VIN and repair order, ask for a case number, and keep every receipt.

Questions

Is my Sonata Hybrid in the lifetime Theta II settlement?

No. That settlement covers the gas 2.4L and 2.0T GDI Sonatas. Sonata Hybrids and Plug-Ins are on the Engine II list instead, with 15 years/150,000 miles of coverage for connecting-rod bearing damage if KSDS was done first.

Is the Optima Plug-In Hybrid included?

Yes, the 2017-2020 Optima Hybrid and Plug-In Hybrid with the Nu 2.0 GDI hybrid engine are listed for Engine II. Confirm your VIN with a Kia dealer.