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2017 Kia Optima

Owner reports · Recalls · Investigations

Similar to other model years

Owner complaints for the 2017 Kia Optima do not stand out strongly from the model-year median of 186.5.

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When problems were reported

Mileage at the reported incident

86 reports with mileage · 169 unknown

NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.

What to inspect

Issues worth paying extra attention to based on owner reports.

  • Engine. Review the 164 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Electrical System. Review the 25 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 21 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

4 crash reports9 fire reports2 injury reports

Fuel/propulsion System complaints

20 reports
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Mileage unknown · Jun 3, 2026
EngineFuel/propulsion SystemPower Train

Loosing oil putting oil in every 3 to 4 days no leaks on ground or oil pan or drain plug.oil don't smell or looks burnt happened around did 2 oil changes in a week still the same. Car will sputer hesitation on acceleration every so often

NHTSA ODI #11741793

Mileage unknown · May 1, 2026
EngineFuel/propulsion System

Constant Mis-firing, must put oil in car every 3 to 4 weeks. Hesitation when driving and sputtering.

NHTSA ODI #11735036

Mileage unknown · Apr 16, 2026
Electrical SystemFuel/propulsion System

The electrical wiring harness connecting to the hybrid system electric fuel pump(s) was found to have significant corrosion and a missing factory-installed protective covering. This is a manufacturing defect. The protective covering was never installed at the factory, leaving the wiring exposed to moisture and corrosion from the…

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The electrical wiring harness connecting to the hybrid system electric fuel pump(s) was found to have significant corrosion and a missing factory-installed protective covering. This is a manufacturing defect. The protective covering was never installed at the factory, leaving the wiring exposed to moisture and corrosion from the time the vehicle was built. COMPONENT THAT FAILED: Electrical wiring harness to hybrid electric fuel pump(s). Missing factory protective covering caused corrosion. The failed component is available for inspection upon request. SAFETY RISK: Corroded wiring in a hybrid vehicle electrical system poses serious risks including electrical shorts, potential fire hazard, and sudden loss of hybrid propulsion while driving. The vehicle is currently inoperable and unsafe to operate. CONFIRMED BY DEALER: Yes. The vehicle was taken to an authorized Kia dealership where it remained for approximately 8 months. The dealership and manufacturer inspected the vehicle and confirmed the wiring issue but denied warranty coverage. THIRD-PARTY CONFIRMATION: A third-party warranty representative independently reviewed photographic evidence and confirmed the missing protective covering is a manufacturing defect, not wear-and-tear or owner-caused damage. MANUFACTURER RESPONSE: The manufacturer denied warranty repair, falsely claiming the hybrid component warranty does not transfer to subsequent owners. Federal warranty law requires transfer unless explicitly excluded in the warranty terms. WARNING SIGNS: No warning lamps, messages, or symptoms appeared prior to the failure. The defect was hidden beneath the vehicle and not visible during normal operation or routine maintenance.

NHTSA ODI #11731494

Mileage unknown · Feb 6, 2026
EngineFuel/propulsion SystemUnknown Or Other

“My vehicle, a 2017 Kia Optima, had repeated safety issues documented in service records. Despite multiple repair attempts (per attached records), the problem remained unresolved and put my safety at risk. I’m seeking further investigation or resolution.”

NHTSA ODI #11716078

Mileage unknown · Nov 16, 2025
EngineFuel/propulsion System

I own a 2017 Kia Optima with a major internal engine defect. Starting shortly after purchase, the car lost power and consumed fuel unusually quickly. Over time, the engine began burning excessive oil and now produces a loud knocking sound (bearing knock), indicating internal bearing failure. These symptoms are consistent with k…

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I own a 2017 Kia Optima with a major internal engine defect. Starting shortly after purchase, the car lost power and consumed fuel unusually quickly. Over time, the engine began burning excessive oil and now produces a loud knocking sound (bearing knock), indicating internal bearing failure. These symptoms are consistent with known Kia engine defects (bearing wear / piston ring failure). The defect is a serious safety concern: because of weak bearings and high oil consumption, the engine could stall, seize, or catch fire. The dealership has refused to repair or replace the engine. I am reporting this as a safety defect and request NHTSA investigation.

NHTSA ODI #11699628

Mileage unknown · Oct 15, 2025
EngineFuel/propulsion System

I purchased the 2017 Optima Hybrid from Huntington Beach Hyundai on [XXX]. I made sure to double check with the dealer if the engine and hybrid battery were in good condition, in which the salesman reassured me everything is good. The car was driving okay for a while, and I had oil change and tires/alignment changed recently. …

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I purchased the 2017 Optima Hybrid from Huntington Beach Hyundai on [XXX]. I made sure to double check with the dealer if the engine and hybrid battery were in good condition, in which the salesman reassured me everything is good. The car was driving okay for a while, and I had oil change and tires/alignment changed recently. Just barely 4 months in after I owned the car, the incident happened on the night of [XXX]. I was driving on the highway near the Getty going roughly 70 mph up the mountain roads while all of a sudden the "check hybrid system" warning came on in the car. The car immediately went into limp mode, and I did everything I could to slow the car to a complete stop, and stop on the freeway shoulder safely. It was a traumatizing experience to me, as this is a major safety issue with the vehicle, and other cars were travelling really fast in LA mountain areas. I had the car towed to a auto repair shop the next day, the mechanics did a deep inspection and informed me the hybrid inverter has failed. I paid $2,177 to replace the hybrid inverter with the mechanic. The mechanic also informed me while they were test driving they heard a knocking sound from the engine. I did a look up and found out there is a class settlement and safety campaigns on the engine for 2017 Optima Hybrid due to the faulty factory rod bearings, and the 150K miles extended warranty from Kia should apply to replace my faulty engine free of charge. I will be getting my car towed to Car Pros Kia in Huntington Beach on October 15th, 2025, and request the dealer to replace my engine per Kia's extended warranty. I am filing the complaint because the car is having problems after problems in barely 4 months of ownership, in which I believe I have purchased a lemon, or Huntington Beach Hyundai knowingly hid the facts the components were faulty. I have also filed a case with Kia corporate. Attached is the repair invoice for the hybrid inverter. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6

NHTSA ODI #11693506

Mileage unknown · Jul 30, 2025
EngineFuel/propulsion SystemPower Train

While driving my 2017 Kia Optima (Theta II engine) at approximately 115,900 miles, I suddenly experienced engine failure. The vehicle began to stall and produced a burning smell shortly before the engine seized completely. I had the car towed to a Kia dealership, which confirmed an internal engine failure and noted that there we…

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While driving my 2017 Kia Optima (Theta II engine) at approximately 115,900 miles, I suddenly experienced engine failure. The vehicle began to stall and produced a burning smell shortly before the engine seized completely. I had the car towed to a Kia dealership, which confirmed an internal engine failure and noted that there were no signs of external oil leaks or neglect. The failure occurred only 4,500 miles after my last oil change, which was documented and professionally completed. The Kia technician mentioned verbally that this was due to excessive oil consumption and burning — an issue I later found to be widely reported in other Kia vehicles using this engine type. The estimated repair cost is over $14,000, which is more than the value of the vehicle. Despite my warranty being expired, this type of failure appears consistent with known manufacturing defects. I am reporting this for public safety and accountability. The vehicle failed without warning and could have caused a dangerous situation on the road.

NHTSA ODI #11677195

Mileage unknown · Nov 13, 2024
EngineFuel/propulsion System

A auto repair shop said my Kia Optima has a bad knock sensor which is a common problem with those cars. My safety and others was put at great risk when I suddenly lost power on the freeway Problem was confirmed at an independent service center Has not yet been inspected by manufacturer Warning message came up at the same time as…

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A auto repair shop said my Kia Optima has a bad knock sensor which is a common problem with those cars. My safety and others was put at great risk when I suddenly lost power on the freeway Problem was confirmed at an independent service center Has not yet been inspected by manufacturer Warning message came up at the same time as losing power

NHTSA ODI #11625072

Mileage unknown · Aug 11, 2024
EngineFuel/propulsion SystemVehicle Speed Control

The KSDS in my engine is causing engine failure due to the dealership failing to fix the problem when I first experienced stalling, lagging and misfiring of my vehicle, which would often make it shake and I would have to turn the car off and reignite it, sometimes more than once. My safety is at risk when driving, because the …

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The KSDS in my engine is causing engine failure due to the dealership failing to fix the problem when I first experienced stalling, lagging and misfiring of my vehicle, which would often make it shake and I would have to turn the car off and reignite it, sometimes more than once. My safety is at risk when driving, because the vehicle will lag while trying to accelerate in traffic. My mechanic researched the issue and found the recall and Kia said they fixed it when it was issued and they didn’t. My CHECK ENGINE light is flashing now and it continues to lose power. I have contacted Kia about the issue and I’m waiting on a response.

NHTSA ODI #11607864

Mileage unknown · Apr 4, 2024
EngineFuel/propulsion SystemFire

ON [XXX], AROUND 11:30 A.M., I WAS DRIVING [XXX] ON [XXX], GOING ABOUT 78 MPH, JUST PASSED [XXX], WHEN THE LIGHTS ON THE DASH LIT UP, SMOKE STARTED COMING FROM THE BACK OF THE CAR, THEN THERE WAS SMOKE COMING FROM UNDER THE HOOD THEN SMOKE STARTED COMING FROM THE A/C VENTS. THERE WAS A FULL FLEDGE FIRE UNDER MY HOOD. THE GUY DRI…

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ON [XXX], AROUND 11:30 A.M., I WAS DRIVING [XXX] ON [XXX], GOING ABOUT 78 MPH, JUST PASSED [XXX], WHEN THE LIGHTS ON THE DASH LIT UP, SMOKE STARTED COMING FROM THE BACK OF THE CAR, THEN THERE WAS SMOKE COMING FROM UNDER THE HOOD THEN SMOKE STARTED COMING FROM THE A/C VENTS. THERE WAS A FULL FLEDGE FIRE UNDER MY HOOD. THE GUY DRIVING NEXT TO ME, KINDA GESTURED FOR ME TO PULL OVER, ALTHOUGH I WAS ALREADY THINKING I NEEDED TO PULL OVER, THE SHOCK OF WHAT WAS HAPPENING, I LOST MY TRAIN OF THOUGHT. I PULLED OVER AND SO DID THAT GUY, HE HAD A FIRE EXTINGUISHER AND TRIED TO PUT OUT THE FIRE BUT TO NO AVAIL. 5 MINS AFTER I GOT OUT, THE ENTIRE CAR WAS ENGULFED IN FLAMES. IT WAS VERY SCARY AND I AM THANKFUL FOR THAT GUY, BECAUSE I FROZE FOR A MINUTE AND COULDN'T THINK OF WHAT TO DO, I PULLED OVER JUST IN TIME. THE FIRE DEPT WAS CALLED AND IT TOOK THEM AWHILE TO PUT THE FIRE OUT, THE CAR WAS BURNT TO A CRISP, A 100% LOSS. A POLICE OFFICER TOOK MY NAME & PHONE NUMBER AND ARRANGED FOR A TOW TRUCK. I HAD TO ARRANGE FOR SOMEONE TO PICK ME UP FROM THE SIDE OF INTERSTATE I [XXX] AND HAD TO CALL OFF WORK. THE CAR WAS TOWED BY PROFESSIONAL TOWING TAMPA LOCATED - PHONE# 813-242-0610 EXT. 5 EMAIL - DISPATCH@PROTOWTAMPA.COM | WEBSITE - www.professionaltowingtampa.com I SPOKE TO SOMEONE AT THE TOW YARD AND THEY TOLD ME TO BRING THEM THE TITLE TO THE CAR THE NEXT DAY AND SUGGESTED I PAY THE TOWING FEE RIGHT AWAY BEING THAT THE TOTAL AMOUNT DUE INCREASES EVERY DAY. ON [XXX], I BROUGHT THEM THE TITLE TO THE CAR AND PAID THE, I BELIEVE, $285 TOWING & STORAGE FEE. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11581052

Official recalls

3

23V594000 · Latches/locks/linkages:trunk Lid:latch

Aug 24, 2023

Kia America, Inc. (Kia) is recalling certain 2016-2017 Rio, 2016-2018 Optima, 2017-2018 Optima Hybrid and Optima Plug-in Hybrid vehicles. The trunk latch base may crack, preventing the opening of the trunk from the inside. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 401, "Internal Trunk Release."

Consequence & remedy

Consequence: A person inside the trunk compartment may become trapped, increasing their risk of injury.

Remedy: Dealers will replace the trunk latch base subassembly, free of charge. Owner notification letters were mailed October 19, 2023. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC278.

18V907000 · Engine; Fuel System, Gasoline:delivery:hoses, Lines/piping, And Fittings

Dec 19, 2018

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence & remedy

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

Additional source detail variants (2)

Engine

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

Fuel System, Gasoline:delivery:hoses, Lines/piping, And Fittings

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

18V161000 · Hybrid Propulsion System

Mar 8, 2018

Kia Motors America (Kia) is recalling certain 2017-2018 Kia Optima 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 & remedy

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: Kia will notify owners, and dealers will remove the VPD switch and install two newly designed Battery Management Systems (BMS) that contain Overvoltage Protection Devices (OPDs), free of charge. The recall is expected to begin May 2018. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC162.

Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗

NHTSA investigations

3

DP22003 · Loss Of Motive Power

Opened Sep 12, 2022 · Closed Dec 12, 2023

Status: closed (inferred from source dates) · Engine

The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021. The Petitioners cited examples of complaints indicating that the subject vehicles were experiencing rapid loss of engine oil due to oil drain plug back outs, resulting in loss of motive power and/or catastrophic engine damage. Additional complaints were provided which alleged that the oil drain pans lack sufficient structural integrity and are susceptible to cracking. The petition itself can be reviewed at NHTSA.gov under ODI number 11481745. On September 12, 2022, the Office of Defects Investigation (ODI) opened Defect Petition (DP22-003) to evaluate the Petitioners’ request. The Petitioners have provided additional complaints within four supplemental letters dated January 31, 2023, March 21, 2023, May 23, 2023, and August 4, 2023. ODI’s evaluation included the review and analysis of the complaints and supporting information submitted by the Petitioners, as well as additional complaints submitted directly to NHTSA which referenced either the oil drain plug or a crack in the oil pan. After reviewing the available data, ODI has not identified evidence that would support opening a defect investigation into the oil drain pan assemblies of the subject vehicles. Based on a review of the available information, a loss of motive power resulting from an oil drain plug back out has not occurred between the initial sale of a vehicle and the completion of its first oil change. If during an oil change service, a technician fails to remove the existing drain plug gasket before installing a new gasket, it is likely that a proper seal between the drain plug and the oil pan will not be made. An improper seal between the drain plug and oil pan could lead to the backing out on the drain plug, resulting in the sudden loss of oil while driving. Additionally, the provided examples of oil pan cracks were localized to the immediate vicinity of the oil drain plug and/or appeared to be the result of direct-contact with a tool during servicing.  There is no information to support that a vehicle-based defect exists relating to the oil pan assembly, and instead the documented incidents are related to the failure to follow the proper maintenance procedures during oil change service. In October 2023, Hyundai published a Technical Service Bulletin (TSB) that provided detailed instructions for oil change service on its gasoline powered vehicles, specifically highlighting the need to remove and replace the existing drain plug gasket prior to reinstalling the drain plug. After a thorough review of the material submitted by the petitioner, the information already in NHTSA's possession, and the potential risks to motor vehicle safety implicated by the petitioners' allegations, NHTSA does not believe that a formal investigation is warranted. Therefore, the petition is denied. A Federal Register Notice (FRN) further detailing NHTSA’s reasons for denial of the petition will be published. The reference numbers for the complaints to NHTSA cited by the petitioner can be found in the petition submission documents in the public file for DP22-003. To review those complaints and the additional complaints ODI added to its evaluation which are cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

EA21003 · Engine Fires

Opened Dec 22, 2021 · Closed Feb 5, 2024

Status: closed (inferred from source dates) · Engine

On March 29, 2019, the Office of Defects Investigation (ODI) opened two Preliminary Evaluations (PE19-003 on Hyundai and PE19-004 on Kia) to broadly investigate incidents of non-crash fires (regardless of origin or operational status of the vehicle) on various model year Hyundai and Kia vehicles.  During the PE investigations, Hyundai and Kia issued several recalls to address vehicle fires, including those due to engine failures involving various engine types.  The remedies for the engine failure recalls typically involve engine inspection (to detect existing damage), and if necessary, engine replacement.  Additionally, both manufacturers have been installing an engine control software modification known as Knock Sensor Detection Software (KSDS) which is intended to detect impending engine failure, alert the driver, and limit engine power (to lessen likelihood of engine failure).KSDS is being installed under recalls and non-safety field actions, and both companies have extended limited engine warranties (see recall files). On December 22, 2021, ODI upgraded PE19-003 and PE19-004 to this Engineering Analysis (EA21-003, covering both Hyundai and Kia) to evaluate the scope of the prior recalls related to engine failures/fires and the efficacy of the recall remedies for the recalls, as well as the long-term viability of related programs and non-safety field actions being conducted by Hyundai and Kia.  The former issue involved approximately 550,000 MY 2013 Hyundai Elantra, MY 2011 Kia Sorento, and MY 2012-2015 Kia Rio.  The latter issue involved approximately 2.5 million recalled vehicles, which have been identified as displaying potential remedy concerns: Hyundai recalls 15V-568, 17V-226, 20V-746, and 21V-727; and Kia recalls 17V-224, 19V-120, 20V-750, and 21V-844. Regarding the recall scope issue, among all of the scope vehicles identified at EA opening, ODI found only the MY 2011 Kia Sorento vehicles equipped with both the Theta II 2.4L 4-cylinder Multi-Point Injection (MPI) and the Lambda II 3.5L 6-cylinder MPI engines experienced relatively high rates of reported fires.  In December 2023, Kia issued recall 23V-877 that will cover about 80,000 MY 2011 Kia Sorento vehicles equipped with the Theta II 2.4L MPI engines.  The remedy will involve an inspection, and if necessary, a replacement of the engine, as well as the installation of KSDS.  It should be noted that in 2021 these vehicles were included in a KSDS product improvement campaign with warranty extension.  For the MY 2011 Sorento vehicles equipped with the Lambda II 3.5L engines, ODI believes that future engine failures/fires involving these vehicles will likely be due to a lax in adhering to the proper or scheduled engine maintenance (regular engine oil changes), rather than a design or manufacturing engine issue. Regarding the issue of the efficacy of the recall remedies, ODI found the majority of the recalled Hyundai and Kia vehicles, by model, experienced lower reported fire rates after the remedies were applied.  Furthermore, ODI found that for most vehicles that did not receive the recall remedies, by model, experienced relatively high fire rates.  To address this problem, Hyundai informed ODI in December 2023, that it will renotify all of its owners covered by the Hyundai recalls of engine failures/fires every 8 months for the next 3 years.  In December 2023, Kia stated that it will renotify the majority of its owners every 8 months for the next 3 years.Several previously recalled Kia models are excluded from the renotification due to their lower reported rates of engine fires.  Overall, the renotification actions will help to increase the recall completion rates, thus reduce the frequency of engine fires in the future. In view of the recall action being taken by Kia and renotification actions being taken by both Kia and Hyundai, ODI is closing this Engineering Analysis.  Also, both companies have been released from the 2020-iniated Consent Orders (Kia since November 2022 and Hyundai since November 2023).  The agency reserves the right to take additional action if warranted by future circumstances.  To review the reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

EA19001 · Electrical Overstress

Opened Apr 19, 2019 · Closed Sep 19, 2024

Status: closed (inferred from source dates) · Air Bags: Air Bag/restraint Control Module

The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect.  During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW.  The ECU receives signals from crash sensors mounted in the vehicle and deploys the vehicle air bags and seat belt pretensioners in accordance with manufacturer design specifications.  The ECU in the subject vehicles contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signal, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes). In September 2016, FCA announced recall 16V-668 for certain model year (MY) 2010 to 2014 Chrysler, Dodge and Jeep products manufactured with the subject ZF-TRW ACU.  In this recall, FCA discussed an EOS condition that resulted in a failure of the subject DS84 ASIC, which caused air bag non-deployment.  FCA noted that the defect condition had only been observed in vehicles equipped with sensor harnessing routed across the front of the vehicle.  Other FCA vehicles that also used the subject ACU, but were not equipped with cross-car harnessing, had not experienced EOS failures, despite similar time in service. During the course of this investigation, ODI sent two separate Information Request (IR) letters to six vehicle manufactures (including FCA, Hyundai, Honda, Kia, Mitsubishi, and Toyota) and one IR letter to ZF-TRW.  These IR letters resulted in ODI receiving comprehensive data from these manufacturers and suppliers. Studies of this data found that the DS84 ASIC does not have sufficient protection against negative electrical transients or electrical overstress (“EOS”) that can be generated in certain severe crashes.  An electrical transient occurs when the electrical power supplied to a circuit changes momentarily over a short duration of time.   In these severe crash cases, the crash sensors and other powered wiring can be damaged and short circuited so as to create a negative electrical transient of sufficient intensity and duration (that are outside the vehicle manufacturer's specification) to damage the ASIC before the restraint device deployment signal is received by the SRS ECU.  This damaged signal can lead to incomplete or nondeployment of the air bags and/or pretensioners.  Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.A total of 8 fatalities and 14 injuries were associated with known EOS events. The common element in all investigated manufacturers vehicles is the SRS ECU containing a DS84 ASIC manufactured by ZF-TRW.  The risk associated with the ASIC is equally shared among all OEMS involved in the investigation.  The actual real-world risk can be mitigated by other factors which were assessed by ODI during this investigation. The first mitigating factor involves protections built into the ACU design which protect the DS84 ASIC from damage.  There are multiple strategies and levels of protection employed by different OEMs that provide effective EOS mitigation.  The two most common strategies at the ACU level are circuit protection diodes on the remote senor signal lines, and current limiting resistors that protect critical components. The second mitigating factor is found at the vehicle level and involves the location and routing of the wires leading from the crash sensors to the SRS ECU.  If the wires are well protected in a crash and are not routed with other power wires carrying large currents, the risk for an EOS event is significantly reduced or eliminated. These design specific factors combine to produce a spectrum of risk for the vehicles equipped with ACUs using the DS84 ASIC.  Given the many of years of field exposure, it is possible to divide the subject population into two groups; vehicles which have experienced EOS events, and vehicles which have not experienced EOS field events. Four of the six OEMs involved in this investigation have experienced EOS field events on at least one of their models equipped with a DS84 ASIC.  All vehicle models (including the Toyota models identified in the Failure Report Summary of the opening resume for this investigation) with field events have been recalled.  In an abundance of caution, ODI kept this investigation open five years to monitor field performance and did not identify any field events on vehicles not included in existing safety recalls. Given the spectrum of risk identified in this investigation and that all vehicles with a demonstrated unreasonable risk have been recalled, ODI is closing this investigation. ODI is closing this investigation with the following manufacturer safety recalls: 16V-668, 18E-043, 18V-137, 18V-363, and 20V-024.  With the recall actions taken by the subject vehicle and equipment manufacturers, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exists on other model or model year vehicles outside of the recall scopes. The agency reserves the right to take further action if warranted by the circumstances.