Diagsheet

2020 Kia Optima · symptom sheet

Check engine light or misfire

  • 29owner reports
  • 98,000median miles
  • 0involved a crash

Newest report May 27, 2026 · checked Sep 9, 2026

112 of the 143 complaints on this car are about the engine. 29 of those describe misfire.

Tick what matches of 29 reports

7
1
11
3
9

What got replaced

Owners who name the part that was replaced mention the sensor (6 reports) and the spark plugs (3 reports).

Recalls and investigations

No recall on the engine covers the 2020 model year as of Sep 9, 2026.

NHTSA investigations into the engine on the Optima

DP22-003opened Sep 12, 2022
Engine · model years 2005 to 2020

Loss of motive power. Closed dec 12, 2023.

NHTSA summary
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 as
EA21-003opened Dec 22, 2021
Engine · model years 2011 to 2017

Engine fires. Closed feb 5, 2024, led to recall 23V-877.

NHTSA summary
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
PE19-004opened Mar 29, 2019
Electrical · model years 2011 to 2014

Non-crash vehicle fires. Closed dec 22, 2021, led to recall 20V-088.

NHTSA summary
During this Preliminary Evaluation (PE), the Office of Defects Investigation (ODI) assessed the scope, frequency and potential safety-related consequences of non-crash vehicle fires caused by both engine failures and failures of other vehicle systems/components in model year (MY) 2011-2014 Kia Optima, MY 2011-2014 Kia Sorento and MY 2010-2015 Kia Soul vehicles equipped with Theta II, Gamma, Nu and Lambda II engines (approximately 1.7 million vehicles). ODI also reviewed field and other data on other Kia vehicles (approximately 3.6 million additional vehicles) equipped with the same engines used in the above-mentioned vehicles.As a result of this PE, Kia has issued NHTSA Recalls 20V-750 and 21V-844 to address potential engine failures and fires in certain Kia vehicles equipped with various engine types.Additional information on these and other related recall actions is available in the downloadable version of this resume available at NHTSA.gov.In addition, ODI has upgraded this PE to an Engineering Analysis (EA) 21-003 which will focus on potential recall scope concerns and recall remedy concerns related to the engine failure-related recalls mentioned above and conducted previously.See the EA21-003 Opening Resume available at NHTSA.gov for more information.Also available in the downloadable version of this resume is a list of the reference numbers for the 444 ODI reports, or Vehicle Owner Questionnaires (VOQs), cited above which ODI received through mid-November 2021.Note that
DP18-003opened Aug 21, 2018
Electrical · model years 2011 to 2014

Non-crash vehicle fires. Closed may 10, 2019, led to recall 18V-907.

NHTSA summary
In a letter dated June 11, 2018, the Center for Auto Safety (CAS) petitioned the National Highway Traffic Safety Administration (NHTSA) to initiate a safety defect investigation into non-collision related fires on model year (MY) 2011-2014 Kia Optima and Sorento, and Hyundai Sonata and Santa Fe vehicles. In a letter dated July 24, 2018, CAS requested that MY 2010-2015 Kia Soul vehicles be added to the petition. CAS stated that there is a higher number of complaints to NHTSA regarding non-crash fires on these vehicles compared to other similar vehicles. The Office of Defects Investigation (ODI) had already opened Recall Queries (RQ17-003 and RQ17-004) on all Kia and Hyundai vehicles equipped with Theta II engines for engine failures that may cause stalling and fires.The queries cover most of the petition subject Optima, Sorento, Sonata, and Santa Fe vehicles but not any of the subject Soul vehicles.On August 21, 2018, ODI opened a Defect Petition (DP18-003) to evaluate whether to grant or deny the CAS petition. ODI sent Information Request letters to Kia and Hyundai (September and October 2018) requesting information on all engine and non-engine related fires in the petition vehicles.ODI performed extensive analysis on the information obtained from Kia and Hyundai. During the DP18-003 analysis, Kia and Hyundai each initiated three additional safety recalls related to engine compartment fires on certain petitioned and non-petitioned vehicles (nearly 740,000 total vehicles: Reca
RQ17-003opened May 18, 2017
Engine · model years 2011 to 2014

Scope and timeliness. Closed dec 22, 2021, led to recall 17V-224.

NHTSA summary
NHTSA opened Recall Query (RQ) 17-003 to investigate the timeliness and scope of Kia?s Theta II GDI engine recall (Recall No. 17V-224), and Kia?s compliance with reporting requirements. On November 23, 2020, the Agency entered into a Consent Order with Kia to administratively resolve NHTSA?s assertions of violations of law in connection with RQ17-003. NHTSA?s assertions included that Kia may be liable for civil penalties on multiple grounds, including that Recall No. 17V-224 was untimely and Kia?s recall report contained certain inaccuracies.Under the Consent Order, Kia agreed to a total civil penalty of $70,000,000. The total civil penalty included a payment of $27,000,000 as a Non-Deferred Amount.Kia also agreed to a sum of $27,000,000 as an Abeyance Amount to be deferred and held in abeyance pending its satisfactory completion, as reasonably determined by NHTSA, of the requirements of the Consent Order.Kia also agreed to a $16,000,000 Performance Obligation Amount to be expended by Kia to fulfill specified Safety Data Analytics Infrastructure obligations. The Consent Order also includes other terms designed to enhance Kia?s safety practices, and requires Kia to retain a Third-Party Auditor who directly reports to NHTSA.Other than RQ17-003, the Consent Order is not intended to affect any other current or future investigation of NHTSA which may involve vehicles equipped with Theta II GDI engines. In particular, Engineering Analysis (EA) 21-003 (which is upgraded from Prelimi

When it happens

The middle half of failures fell between 50,000 and 118,000 miles, from the 13 reports that gave a mileage.

122
323
724
1325
526

What owners wrote

“When the vehicle was about 3 years old and at 60,000 miles, the fuel injector went out. Kia took weeks to approve the replacement under warranty. Since then the engine light came on and said cylinder 3 has leak and fouls the plug. We've had it repaired 3 times. The mechanic said it would be too costly to repair and the engine should be replaced.”

Filed May 27, 2025 · 60,000 miles

“I was driving down the interstate and all of a sudden the blinking lights of the check engine light came on and automatically I went from 75 mph down to 63 mph and when I looked up what it was, it was the knock detection system of the 2020 Kia Optima. I could not accelerate beyond 63 mph and I fear that the engine might stall on me so I went to O’Reillys and have them check it and it says it’s the P1326 Code”

Filed May 1, 2025

“Accelerating at a normal rate to get on the highway and the check engine light starts flashing out of nowhere and car goes into limp mode. Made it to local shop and they informed me it was a P1326 code and that a knock sensor would have to be replaced, but that Kia has recalled the older models for this same reason.”

Filed Apr 9, 2025

“Was on highway going 65, check engine light started flashing loss power. Couldn't go over 2000 rpms car would struggle to accelerate, car had been using up oil like crazy the week before. Stopped at an autozone car read code P1326.”

Filed Oct 13, 2024

Should you keep driving it?

This page can't tell you that. 0 of 29 reports involved a crash. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.

File your own report with NHTSA. Complaint counts are how a problem gets an investigation.

Other problems on this car