Code P1326, Faulty Knock sensor on 2.4GDI
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.
About this comparison →How this year compares
Owner complaints by model year
Compare all Optima years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
All reported categories
Tap a category to read its complaints. One report may name several components.
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.
Engine complaints
164 reportsThe car stalled out
My Kia optima fe 2017 has been consuming a lot of motor oil it takes a quart every 2 to 3 weeks and of if I drive it more than average it needs motor oil sooner
Engine is failing and using over 3 quarts of oil every 700-100 miles. Spark Plugs have become oil fouled and replaced all 4 spark plugs June 11th, 2024 and replaced all 4 spark plugs again January 12th, 2025. Today July 7th, 2025 Check Engine light came back on with Engine Misfire code P0303 Cylinder 3 Misfire, changing spark pl…
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Engine is failing and using over 3 quarts of oil every 700-100 miles. Spark Plugs have become oil fouled and replaced all 4 spark plugs June 11th, 2024 and replaced all 4 spark plugs again January 12th, 2025. Today July 7th, 2025 Check Engine light came back on with Engine Misfire code P0303 Cylinder 3 Misfire, changing spark plugs again today. My safety is put at risk because oil consumption is a know issue with Kia GDI Engines. At any moment my car can run out of oil if it is not check every other week causing my engine to completely fail or a spark plug become Oil fouled and a spark plug needing to be replaced. In July of 2024 when this happened I was on the highway going 70 mph and my car just completed shut down. I could have been seriously injured had I not been able to pull over and only been 5 miles away from my home. I called Kia today to start an Oil Consumption test, stated I am the 2nd owner and while this is a known issue I will pay for and Upper Engine Clean which is only a band aid. This problem has been confirmed with Kia that the GDI Engines are consuming oil. I have also replaced all Engine Coolant, Coolant Temperature Senor, Thermostat as well as the PCV Valve.
My vehicle is experiencing engine issues consistent with the known Theta II GDI engine defects — including rod bearing failure piston rings engine stalling, I understand that Kia has offered extended warranty coverage through the engine defect settlement, provided the Knock Sensor Detection System (KSDS) update was installed …
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My vehicle is experiencing engine issues consistent with the known Theta II GDI engine defects — including rod bearing failure piston rings engine stalling, I understand that Kia has offered extended warranty coverage through the engine defect settlement, provided the Knock Sensor Detection System (KSDS) update was installed before failure. I am unsure whether this update has been applied and would like to confirm my eligibility. I respectfully request: 1.Confirmation of KSDS update installation on my VIN 2.A review of my eligibility for engine inspection and coverage under the extended warranty 3.Assistance with coordinating service and coverage at my local dealership (LeBlanc Kia, New Iberia, LA) I am the second owner of this vehicle and want to ensure I am treated fairly under the known warranty extension guidelines. Thank you for your support. I look forward to your prompt response.
Engine stalled out while driving lyft. Got passenger to their destination safely, however lyft is my only source of income big risk to stall out on a highway.
I purchased a 2017 Kia Optima from Deal Makers Auto Sales in Georgia in February 2024. The vehicle broke down within 3 months. I later found out it had four open safety recalls that were never disclosed at the time of sale. This is dangerous and deceptive, and the dealership refused to take responsibility or make repairs.
The contact owns a 2017 Kia Optima. The contact stated that while attempting to start the vehicle, the vehicle lost motive power with no warning light illuminated. The vehicle was towed to an independent mechanic, where it was diagnosed and determined that the engine had failed and needed to be replaced. The vehicle was not repa…
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The contact owns a 2017 Kia Optima. The contact stated that while attempting to start the vehicle, the vehicle lost motive power with no warning light illuminated. The vehicle was towed to an independent mechanic, where it was diagnosed and determined that the engine had failed and needed to be replaced. The vehicle was not repaired. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 80,000.
I was driving on the highway, the check engine light started flashing and the car lost power. This created a very dangerous situation because I could not go the speed limit and could not get off the highway since I was in the middle lane. We went and had the check engine light checked and were told the code was P1326.
I was driving on the highway and randomly my car started to shake very badly and i couldn’t go faster than about 30 mph. My engine light didn’t turn on until i turned the car off and back on after finally making it home after almost getting hit by cars trying to make it back home. I sent it to get looked at and they said that it…
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I was driving on the highway and randomly my car started to shake very badly and i couldn’t go faster than about 30 mph. My engine light didn’t turn on until i turned the car off and back on after finally making it home after almost getting hit by cars trying to make it back home. I sent it to get looked at and they said that it’s misfiring pretty severely and that kia had a recall on an engine/motor awhile back for my car and to take it to a dealership. I contacted KIA customer care but the only recall I see when I look up my VIN # is for the trunk recall.
Official recalls
323V594000 · 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
3DP22003 · 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.
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