Kia bulletin SC340
What it saysVoluntary emissions service campaign: theta II 2.4L GDI emissions: ECM logic improvement (SC340 revision 5) - this bulletin has been revised to include additional information. NHTSA’s full summary ↓
Kia filed this with NHTSA as an emissions communication dated Apr 4, 2026, received Oct 24, 2025, about the engine — 20 documents under this number: SC340_TSB_R5, SC340_OWNR_NQ5_105, SC340_OWNR_JF&JFA_104, SC340_TSB_R4 and 16 more. It names 17 model years (2016–2022). An emissions communication is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationWhat it applies to, as the document itself states it — the build window in the manufacturer’s own words, read by machine from the PDF NHTSA serves. The build date is on the certification label in the driver’s door jamb; the dealer settles a borderline vehicle by its VIN.
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.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| SC340_TSB_R5 | Emissions | Apr 4, 2026 | 11031854 | PDF, 756 KB |
| SC340_OWNR_NQ5_105 | Emissions | Mar 17, 2026 | 11030391 | PDF, 124 KB |
| SC340_OWNR_JF&JFA_104 | Emissions | Mar 17, 2026 | 11030390 | PDF, 124 KB |
| SC340_TSB_R4 | Emissions | Mar 6, 2026 | 11029979 | PDF, 942 KB |
| SC340_OWNR_UM103 | Emissions | Dec 19, 2025 | 11026900 | PDF, 124 KB |
| SC340_OWNR_JF103 | Emissions | Dec 19, 2025 | 11026899 | PDF, 124 KB |
| SC340_OWNR_QL103 | Emissions | Dec 19, 2025 | 11026898 | PDF, 124 KB |
| SC340_TSB_R3 | Service bulletin | Dec 10, 2025 | 11026533 | PDF, 901 KB |
| SC340_OWNR_JF101 | Emissions | Nov 27, 2025 | 11025897 | PDF, 124 KB |
| SC340_OWNR_QL101 | Emissions | Nov 27, 2025 | 11025895 | PDF, 124 KB |
| SC340_OWNR_UM101 | Emissions | Nov 27, 2025 | 11025894 | PDF, 124 KB |
| SC340_TSB_R2 | Service bulletin | Nov 21, 2025 | 11025892 | PDF, 724 KB |
| SC340_OWNR_JF102 | Emissions | Nov 7, 2025 | 11025898 | PDF, 185 KB |
| SC340_TSB_R1 | Service bulletin | Nov 7, 2025 | 11025859 | PDF, 920 KB |
| SC340_TSB | Service bulletin | Nov 5, 2025 | 11025889 | PDF, 922 KB |
| SC340_STKR | Emissions | Oct 23, 2025 | 11024469 | PDF, 417 KB |
| SC340_QA | Emissions | Oct 23, 2025 | 11024468 | PDF, 114 KB |
| SC340_POC | Emissions | Oct 23, 2025 | 11024467 | PDF, 152 KB |
| SC340_DPSM | Emissions | Oct 23, 2025 | 11024462 | PDF, 114 KB |
| SC340_DP | Emissions | Oct 23, 2025 | 11024445 | PDF, 135 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 17 model years this bulletin names have filed 5,624 complaints with NHTSA since 2015. 3,784 of them name Engine, Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2016 Kia Sorento, the 203 owners who gave an odometer reading for Engine reported it at a median of 85,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
I've had this car going on three years sometimes not all the time I will go to start it and it will barely start so I took it to the dealership three times when I got my oil change and they checked the battery but they're saying the battery is good and the starting system the car will just be sitting in my garage and I try to start it it…
2019 Kia Optima · Electrical System · filed with NHTSA May 9, 2021 · ODI 11415708
I was driving back home I had too work in rodeo california half the way everything was going great I had my 3 children with me my car didn't gave me any warning no check engine light.,no white smoke , I was passing the dodger stadium when suddenly my 2018 Sorento just shut down almost got hit I was about too enter the 710 and nooooo I…
2018 Kia Sorento · Engine · filed with NHTSA Aug 26, 2019 · ODI 11246317
The contact owned a 2020 Kia Sportage. The contact was at a red light when a smoke odor was detected and another driver informed him that black smoke was coming from the exhaust. The contact stated that as he was exiting the vehicle, he saw flames igniting under the hood of the vehicle and moments later the vehicle burst into flames.
2020 Kia Sportage · Engine · filed with NHTSA Mar 10, 2021 · ODI 11400126
In depth: 2020 Kia Optima engine problems → · 2019 Kia Optima engine problems → · 2018 Kia Optima engine problems → · 2017 Kia Optima engine problems →
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group24 other manufacturer communications filed against these Kia models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Kia list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| SC365 | Emissions | Sep 10, 2026 | TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: This bulletin provides the procedure to update the emissions‑related logic… |
| PI2108 | Service bulletin | Apr 15, 2026 | PRODUCT IMPROVEMENT CAMPAIGN NU 2.0L GDI - KNOCK SENSOR DETECTION SYSTEM (KSDS) ECU LOGIC IMPROVEMENT (PI2108) - This bulletin provides info… |
| CA2516 | Service bulletin | Apr 1, 2026 | TECHNICAL SERVICE BULLETIN: CUSTOMER ACTION: ECU LOGIC IMPROVEMENT FOR DTC P2B59F0 (CA2516) - This bulletin provides information to upgrade… |
| WTY026_QA | Service bulletin | Mar 18, 2026 | TECHNICAL SERVICE BULLETIN: OIL PRESSURE SWITCH (OPS) REPLACEMENT - This bulletin has been revised to include additional information. New/re… |
| PI2104 | Service bulletin | Mar 18, 2026 | PRODUCT IMPROVEMENT CAMPAIGN: THETA 2.4L MPI - KNOCK SENSOR DETECTION SYSTEM (KSDS) ECU LOGIC IMPROVEMENT (PI2104) - This bulletin provides… |
| SC325 | Emissions | Feb 20, 2026 | TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: AEWP INSPECTION AND REPLACEMENT (SC325) - This bulletin has been revised t… |
| DC26 | Service campaign | Feb 10, 2026 | TECHNICAL SERVICE BULLETIN: DATA COLLECTION: EXTRACT CALIFORNIA EMISSIONS DATA FROM ECU (DC26) - This bulletin has been revised to include a… |
| CA2508 | Service bulletin | Dec 8, 2025 | TECHNICAL SERVICE BULLETIN: ITM REPLACEMENT AND ECM & TCM LOGIC IMPROVEMENT (CA2508) - This bulletin provides information to replace the Int… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Kia, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Kia SC340 a recall?
No. A emissions communication is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the SC340 repair free?
A emissions communication is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does SC340 cover?
The manufacturer filed it against 17 model years: 2020 Kia Optima, 2019 Kia Optima, 2018 Kia Optima, 2017 Kia Optima, 2016 Kia Optima, 2020 Kia Sorento and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone. The document itself sets the build window: 16-20MY Optima (JF, JFa): built 28 Aug 2015 – 23 Jun 2020; 16-20MY Sorento (UMa): built 27 Oct 2014 – 4 Nov 2020; 17-22MY Sportage (QL): built 10 Dec 2015 – 7 Dec 2021 — the build date is on the certification label in the driver’s door jamb.