The 2016 Sonata PHEV shares the problematic 'Theta II' 2.0L turbo engine with non-hybrid Sonatas, inheriting catastrophic bearing and piston failures. Add hybrid complexity to an already fragile powertrain, and you've got a ticking time bomb that can grenade without warning.
Theta II Engine Bearing Failure and Seizure
Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Metallic knocking or rattling from engine bay, especially cold starts, Metal shavings in oil during changes, Check engine light with rod bearing codes (P1326), Sudden loss of power or complete engine seizure while driving
Fix: Complete engine replacement or rebuild required. Hyundai extended warranty covers some cases, but many fall through cracks. Short block replacement: 18-24 hours labor. Full rebuild with machining: 25-30 hours. OEM reman engine swap: 16-20 hours.
Estimated cost: $6,500-11,000
Hybrid Battery Cooling System Failure
Occasional · high severity
Typical onset: 80,000-140,000 mi
Symptoms: Hybrid system warning light with reduced power mode, Battery overheating messages on dash, Loss of electric-only range, Cooling fan runs constantly or not at all
Fix: Battery cooling fan motor or control module replacement. Fan motor: 3-4 hours labor. If coolant leak damaged battery cells, entire high-voltage battery replacement required: 8-12 hours labor plus $3,000-5,000 battery pack.
Estimated cost: $800-6,500
Transmission Oil Cooler Leaks
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Pink or red fluid puddles under vehicle, Transmission slipping or delayed engagement, Milky or discolored transmission fluid (coolant contamination), Overheating transmission warnings
Fix: Oil cooler replacement and complete fluid flush. Cooler buried behind timing cover on this hybrid layout: 6-8 hours labor. If coolant mixed with ATF, internal transmission damage likely—add valve body or full rebuild.
Estimated cost: $1,200-4,800
Motor-Driven Power Steering (MDPS) Failure
Occasional · high severity
Typical onset: 50,000-90,000 mi
Symptoms: Complete loss of power steering assist suddenly, MDPS warning light illuminated, Steering wheel becomes extremely stiff at low speeds, Grinding or whining noise when turning
Fix: MDPS motor/ECU assembly replacement. Unit mounted on steering column: 4-5 hours labor. Common TSB (15-ST-002) covers some units, but many out of extended coverage window by now.
Estimated cost: $1,400-2,200
12V Battery Drain from Hybrid System Parasitic Draw
Common · medium severity
Symptoms: Dead 12V battery after 2-3 days of sitting, Hybrid system won't initialize (READY light won't come on), Multiple warning lights on startup, Clicking from under hood when trying to start
Fix: Hybrid control module stays partially awake, draining battery. Software updates available but don't always fix it. 12V battery replacement plus parasitic draw diagnosis: 2-3 hours labor. May need HCU replacement if software flash fails: 4-5 hours.
Estimated cost: $350-1,800
Charge Port Door Actuator Freezing/Binding
Occasional · low severity
Symptoms: Charge port door won't open electrically, Door opens but won't close/latch, Actuator motor grinding noise, Warning message 'Charge port door open' when closed
Fix: Charge port door actuator replacement. Poor seal design lets water in. 1.5-2 hours labor. Preventive: silicone spray on mechanism every 6 months.
Estimated cost: $400-650
Onboard Charger (OBC) Failure
Rare · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Vehicle won't charge from Level 1 or Level 2, Charging starts then immediately stops, Check hybrid system warning, Burning smell from under hood during charge attempts
Fix: Onboard charger module replacement. Located under hood near battery: 5-6 hours labor. Hyundai redesigned unit for later years due to overheating issues.
Estimated cost: $2,200-3,500
Owner tips
Check Hyundai's engine recall/extended warranty status immediately—VIN lookup can save you $8k if bearing failure happens
Change engine oil every 5,000 miles maximum with quality synthetic—this engine cannot tolerate extended intervals
Monitor hybrid battery fan operation monthly; listen for abnormal sounds during charging
Keep 12V battery on tender if car sits unused more than a week to prevent hybrid system lockout
Avoid letting high-voltage battery sit at 100% charge for extended periods—accelerates cell degradation
Hard pass unless under comprehensive warranty—the Theta II engine failure risk alone makes this a financial liability waiting to happen, and adding hybrid complexity just multiplies the expensive failure points.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
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Hyundai Motor America (Hyundai) is recalling certain 2015-2017 Sonata, 2016-2017 Sonata Hybrid, and Sonata Plug-In Hybrid vehicles. The Smart Junction Box (SJB) software logic may not properly interpret the signals received from the multifunction switch, which could cause the turn signal to activate in the opposite direction of what the driver intended.
Consequence: A turn signal that activates in the opposite direction of what was intended by the driver increases the risk of a crash.
Remedy: Dealers will update the SJB software, free of charge. Owner notification letters were mailed November 19, 2021. Owners may contact Hyundai customer service at 1-855-371-9460. Hyundai's number for this recall is 210.
HYBRID PROPULSION SYSTEM · 18V166000
2018-03-12
Hyundai Motor America (Hyundai) is recalling certain 2016-2018 Hyundai Sonata Plug-In Hybrid vehicles. These vehicles are equipped with a Voltage Protection Device (VPD), designed to protect the high voltage battery module, that may activate inadvertently.
Consequence: If the VPD activates while the vehicle is being operated in Electric Vehicle (EV) mode, there may be a loss of power, increasing the risk of a crash.
Remedy: Hyundai will notify owners, and dealers will remove the VPD switch and install a new Battery Management System (BMS) that contains an Overvoltage Protection Device (OPD). The recall is expected to begin May 2018. Owners may contact Hyundai customer service at 1-855-371-9460. Hyundai's number for this recall is 175.
PARKING BRAKE:INDICATOR LIGHT · 17V359000
2017-06-05
Hyundai Motor America (Hyundai) is recalling certain 2015-2016 Sonata and Genesis vehicles. In the affected vehicles, the warning light to indicate that the parking brake is applied may intermittently not illuminate in the dash due to corrosion in the switch.
Consequence: If the parking brake indicator is not illuminated when the parking brake is applied, the driver may operate the vehicle with the parking brake partially engaged, increasing the risk of a crash.
Remedy: Hyundai will notify owners, and dealers will replace the parking brake switch, free of charge. The recall began on August 4, 2017. Owners may contact Hyundai customer service at 1-855-671-3059. Hyundai's number for this recall is 164.
VISIBILITY:SUN/MOON ROOF ASSEMBLY · 16V726000
2016-10-11
Hyundai Motor America (Hyundai) is recalling certain model year 2015-2016 Sonata Hybrid vehicles manufactured December 8, 2014, to August 18, 2015, and Hyundai Sonata vehicles manufactured May 28, 2014, to March 18, 2016, equipped with the panoramic sunroof option. Due to a bonding issue with the sunroof wind deflector, the sunroof panel on the affected vehicles may detach while driving.
Consequence: If the sunroof detaches from the vehicle it could become a road hazard, increasing the risk of a crash.
Remedy: Hyundai will notify owners, and dealers will repair the wind deflector anchor plate, free of charge. The recall began December 2016. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 152.
AIR BAGS · 16V615000
2016-08-24
Hyundai Motor Company (Hyundai) is recalling certain model year 2016 Sonata vehicles manufactured March 28, 2016 through April 12, 2016. The affected vehicles have a driver-side frontal air bag that may not adequately protect the driver's neck from injury in the event of a crash. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 208, "Occupant Crash Protection."
Consequence: A frontal air bag that does not adequately protect the driver's neck may increase their risk of injury in the event of a crash.
Remedy: Hyundai will notify owners, and dealers will replace the driver's frontal air bag module, free of charge. The recall began October 14, 2016. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 148.
AIR BAGS:FRONTAL · 16V232000
2016-04-21
Hyundai Motor Company (Hyundai) is recalling certain model year 2015-2016 Sonata vehicles manufactured May 29, 2014 to February 11, 2016, 2017 Elantra vehicles manufactured January 12, 2016 to February 22, 2016, and one 2016 Sonata Hybrid vehicle manufactured October 15, 2015. In these vehicles, the driver's frontal air bag may be missing a chemical enhancer required for the second stage air bag deployment, resulting in the second stage not deploying in certain crashes. The primary stage will deploy as intended.
Consequence: An air bag that does not inflate increases the risk of injury.
Remedy: Hyundai will notify owners, and dealers will replace the driver's frontal air bag module, free of charge. The recall began on May 5,2016. Owners may contact Hyundai customer service at 1-855-371-9460. Hyundai's number for this recall is 144.
Hyundai Motor America (Hyundai) is recalling certain model year 2015-2016 Sonata vehicles manufactured May 28, 2014, to August 21, 2015. The affected vehicles are equipped with an Antilock Braking System (ABS) warning light intended to warn the driver if there is an ABS malfunction. In the event of an ABS malfunction, the Brake System warning light will illuminate, but the ABS warning light will not illuminate. Since the vehicles have ABS malfunction lights that do not illuminate, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 135, "Light Vehicle Brake Systems."
Consequence: If the driver is alerted there is a brake system malfunction, but not specifically with the ABS system, the driver may operate the vehicle unaware that the vehicle's brakes may lock up during hard braking, increasing the risk of a crash.
Remedy: Hyundai will notify owners, and dealers will update the ABS control unit software, free of charge. The recall is expected began on November 30, 2015. Owners may contact Hyundai customer service at 1-855-671-3059. Hyundai's number for this recall is 134.
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