2018 Kia Optima

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.

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.

See attached document for complaint.

NHTSA ID

11752131

Incident

Jun 3, 2026

I was run off the road by a drunk driver I hit a tree at 35MPH MY AIR BAGS DID NOT DEPLOY NOR DID MY SEAT BELT LOCK!!!! I NOW HAVE MULTIPLE INJURIES I HAVE BROKEN BONES ALL THROUGHOUT MY FACE!!!!! A SEVERE CONCUSSION!!!!! Any time I call the the customer care center and try and get information or call someone I either get hung up or gave the run around and then hung up on my mother in law has also tried calling and have received the same response this is so unacceptable and unprofessional.

NHTSA ID

11751435

Incident

Jul 14, 2026

I’ve had my 2018 kia optima for round about two years.I only got this car because they refused to replace my previous engine on my 2015 Kia optima,even though I had a warranty but that’s another story(Kia on the Blvd).This car have given me problems from the start.Going through oil in less than a month,which they can never find a leak,not being able to go over a certain speed before I start to hear noises.Ive complained about noises,they act like they can’t hear,and said nothing is wrong with the engine when previously checked.My check engine light has came on twice and both times the car was malfunctioning on the highway resulting in me have to get a tow.First it was plugs replacement now I need a whole new engine.I really don’t know what to do at this point.I believe they sold me a faulty car

NHTSA ID

11749282

Incident

May 23, 2026

Purchased vehicle from a used car dealership. Had it a few months before brake pedal started losing pressure and going to floor. Had master cylinder replaced. A few months later, brake light started coming on when accelerating. New master cylinder had leaked into brake booster. Had master cylinder replaced along with brake booster. A few weeks later and brake pedal is losing pressure again

NHTSA ID

11748040

Incident

Jan 6, 2026

The car burns oil within a week of getting an oil change. It was only driven a 200 miles before all of the oil was burned out. This has been a consistent issue with this car that the oil burns at an extreme rate. This is a safety risk as it could lead to engine overheating, the engine could stall out due to the fast burning of the oil, or a potential fire hazard while driving. The oil light will come on for a second and at that point, the oil is already EXTREMELY too low. I brought the car to the mechanic and they have told me multiple times that there is no leak or anything. The mechanic says that the car simply is burning oil too fast.

NHTSA ID

11746528

Incident

Jun 15, 2026

The contact owns a 2018 Kia Optima. The contact stated that while driving at an undisclosed speed, there was an abnormal odor and a knocking sound coming from the engine. The vehicle was taken to the dealer; however, the dealer was unable to duplicate the issue. The vehicle was not repaired. The issue persisted. The contact stated that the vehicle was later returned to the dealer to be repaired under a service campaign involving the engine control unit (ECU). Shortly after the vehicle was repaired, the ECU failure message was displayed. The vehicle subsequently became inoperable. The vehicle was not repaired. The manufacturer was notified of the issue. The approximate failure mileage was 1,500.

NHTSA ID

11745997

Incident

Aug 29, 2018

Mileage

1,500 mi

2018 Kia Optima Dealer Ed Voyles Kia Smyrna began Recall SC340. Vehicle drove in running. Dealer flashed ECM software, discovered non-original engine/ECU. Vehicle now won’t start. Dealer document states 'will not start after recall.' Dealer refuses to restore to running condition citing prior repairs. This violates 49 USC 30120

NHTSA ID

11743257

Incident

Jun 9, 2026

The contact owns a 2018 Kia Optima. The contact stated that while attempting to accelerate from a standing start the vehicle had experience sever jerking and hesitation. Also, the vehicle has experience oil consumption problems and the contact constantly added engine oil. The cause of the failures were not determine. Also, the hood latch had malfunctioned and the hood could not opened to add oil to the engine. The cause of the failures were not determined. The local dealer and manufacturer were notified of the failures but no assistance was offered. The failure mileage was 121,000.

NHTSA ID

11736008

Incident

May 6, 2026

Mileage

121,000 mi

TECHNICAL SERVICE BULLETIN: CUSTOMER SATISFACTION: THEFT DETERRENT IGNITION CYLINDER PROTECTOR AND DECAL INSTALLATION (CS2312) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to install a Theft Deterrent Ignition Cylinder Protector on certain 2010-2022MY Kia vehicles outlined on page 20, which may not have been equipped with an immobilizer and whose Integrated Body Control Unit (IBU) / Body Control Module (BCM) did receive the Anti-Theft Software Logic upgrade under CS2301/02/03/04/05/06/07/08/09 TSBs. In an effort to help prevent thefts of Kia vehicles, a protective cover will be permanently affixed to the ignition cylinder. This Theft Deterrent Ignition Cylinder Protector prevents the removal of the key lock cylinder thereby preventing access to the ignition tumbler.

VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSIONS: ECM LOGIC IMPROVEMENT (SC340 REVISION 5) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2020MY Optima, 2016-2020MY Sorento, 2017-2022MY Sportage vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations may cause the vehicle to release air pollutants which exceed Federal and California standards. These standards were established to protect your health and welfare from the dangers of air pollution.

VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 104 ) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2016-2020 MY Optima vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.

TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSION SECM LOGIC IMPROVEMENT (SC340 REV 4) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2022MY vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations may cause the vehicle to release air pollutants which exceed Federal and California standards. These standards were established to protect your health and welfare from the dangers of air pollution.

TECHNICAL SERVICE BULLETIN: CUSTOMER SATISFACTION: THEFT DETERRENT IGNITION CYLINDER PROTECTOR AND DECAL INSTALLATION (CS2312) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to install a Theft Deterrent Ignition Cylinder Protector on certain 2010-2022MY Kia vehicles outlined on page 20, which may not have been equipped with an immobilizer and whole Integrated Body control Unit (IBU) / Body Control Module (BCM) did receive the Ant-Theft Software Logic upgrade under CS2301/02/03/04/05/06/07/08/09 TSBs. In an effort to help prevent thefts of Kia vehicles, a protective cover will be permanently affixed to the ignition cylinder. This Theft Deterrent Ignition Cylinder Protector prevents the removal of the key lock cylinder thereby preventing access to the ignition tumbler.

VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 103 / JF) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2016-2020 MY Optima vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.