2014-2021 Kia Theta II GDI ECM Logic Improvement SC340

Why This Matters

Kia has identified that certain 2014-2021 Kia Optima, Sorento, and Sportage vehicles equipped with 2.4L Theta II GDI engines may have engine calibrations that were not fully optimized for specific emissions standards. This can lead to the vehicle releasing air pollutants that exceed Federal and California regulations, potentially impacting air quality and public health. The Kia Theta II ECM Logic Improvement is crucial for ensuring these vehicles meet environmental standards.

This voluntary emissions service campaign aims to rectify this issue by updating the Electronic Control Module (ECM) software. The update will improve the vehicle's emissions performance and enhance the Diagnostic Trouble Code (DTC) judgment logic, which helps accurately identify and address engine-related issues.

What's Being Addressed

The core of the SC340 campaign is a software upgrade for the Electronic Control Module (ECM) in affected 2014-2021 Kia vehicles with 2.4L Theta II GDI engines. The engines in these models require updated calibrations to ensure they comply with stringent emissions regulations. This software update is designed to optimize engine performance for environmental compliance.

Beyond emissions, the update also includes an improvement to the ECM's Diagnostic Trouble Code (DTC) judgment logic. This enhancement means the vehicle's onboard diagnostic system will be better equipped to detect and report potential engine issues, leading to more accurate diagnoses and repairs if problems arise. The campaign is identified by the number SC340 (Revision 3, dated 12/10/2025).

Important Warnings for Technicians and Owners

The service bulletin includes several critical warnings to ensure the software update is performed correctly and to prevent damage to the vehicle's systems:

• "Confirm a fully charged battery (12.3 volts or higher is necessary) is used or utilize or fully charged jump starter box connected to the battery."
• "Ensure the KDS GDS is sufficiently charged at 60% or higher to reflash."
• "All ECU upgrades must be performed with the ignition set to the 'ON' position unless otherwise stated."
• "Damaged VCI II units should not be used and promptly replaced."
• "Be careful not to disconnect the VCI-II connected to the vehicle during the ECU upgrade procedure."
• "DO NOT start the engine during ECU upgrade."
• "DO NOT turn the ignition key ‘OFF' or interrupt the power supply during ECU upgrade."
• "When the ECU upgrade is completed, turn the ignition 'OFF' and wait 10 seconds before starting the engine."
• "ONLY use approved ECU upgrade software designated for the correct application."
• "Before attempting an ECU upgrade on any Kia model, make sure to first determine whether the applicable model is equipped with an immobilizer security system. Failure to follow proper procedures may cause the PCM to become inoperative after the upgrade and any claims associated with this repair may be subject to chargeback."
• "If the automatic upgrade fails, turn the ignition 'OFF' for about 10 seconds then place it back in the 'ON' position to reset the control unit BEFORE performing the manual upgrade."
• "DO NOT COMPLETE THE CARD UNLESS THE SERVICE CAMPAIGN WORK IS COMPLETED." (Referring to the Vehicle Emission Recall - Proof of Correction card).

Repair Procedure Summary

The Kia Theta II ECM Logic Improvement involves reprogramming the Electronic Control Module (ECM) with updated software. Technicians must refer to TSB SST081 for detailed software upgrade instructions using the Kia Diagnostic System (KDS) tablet and VCI-II interface. The process typically uses an 'Auto Mode' upgrade, but a 'Manual Mode' option is available if the automatic process fails or is otherwise specified.

Preparation Steps:

1. Confirm the vehicle's battery is fully charged (12.3 volts or higher) or connect a fully charged jump starter box.
2. Ensure the Kia Diagnostic System (KDS) Global Diagnostic System (GDS) tablet is sufficiently charged (60% or higher) for the reflash procedure.
3. Set the vehicle's ignition to the 'ON' position for all ECU upgrades, unless specific instructions state otherwise.
4. Do not use damaged VCI-II units; replace them promptly if necessary.
5. Connect the negative (-) terminal to the battery as shown in the service bulletin's illustration, ensuring a stable power supply during the upgrade.

Software Upgrade Process:

1. Using the KDS tablet, select the 'Auto Mode' ECU Upgrade option. If 'Auto Mode' fails or is not applicable, the 'Manual Mode' option may be used.
2. Select the applicable 'ECM' system module and the correct 'Event Group' for the affected vehicle. The bulletin lists various upgrade events, such as:
   • 889. UMa Theta 2.4 emission logic improvement (18MY)
   • 876.UMa PE Theta 2.4 Emission Logic Improvement (19MY)
   • 877.UMa PE Theta 2.4 Emission Logic Improvement (20MY)
   • 890.JF/JFa Theta 2.4 emission logic improvement (18MY)
   • 878.JFa PE Theta 2.4 Emission Logic Improvement (19-20MY)
   • 891.QL Theta 2.4 emission logic improvement (18MY)
   • 879.QL/QL PE Theta 2.4 Emission Logic Improvement (19-21MY)
   • 914.QL/QL PE Theta 2.4 Emission Logic Improvement (22MY)
3. Verify the vehicle's Calibration Identification of the applicable ECU ROM ID by referencing the extensive information tables provided on pages 3-14 of the bulletin. These tables list specific ECU Part Numbers (e.g., 39100-2GGF8, 39171-2GRA1, 39171-2GRB3) and their corresponding previous and new ROM IDs (e.g., UMAINC4ERDXA, UPAJNC4ERGXA, QPNNLM_A_SXA) for various models, years, and immobilizer configurations.
4. During the ECU upgrade, do not disconnect the VCI-II from the vehicle, do not start the engine, and do not turn the ignition key 'OFF' or interrupt the power supply.
5. Once the ECU upgrade is completed, turn the ignition 'OFF' and wait 10 seconds before starting the engine.
6. Only use approved ECU upgrade software designated for the correct application.

Post-Upgrade Documentation (for specific states):

For vehicles registered in California, Connecticut, Delaware, Massachusetts, Maine, Maryland, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington, the following steps are required:

1. A Vehicle Emission Recall - Proof of Correction card (Part Number: UT161 SC340) must be completed by the Dealership's Service Manager using a permanent ink pen. This card serves as evidence of voluntary service campaign completion for vehicle registration renewal.
2. A Campaign Completion Label (Part Number: UT160 SC340) must be filled out with the Dealer Code and Date, then affixed under the hood of the vehicle, typically near the shock tower. Ensure the mounting surface is cleaned for proper adhesion.

Required Tools or Parts

To perform the Kia Theta II ECM Logic Improvement update, technicians will need the following:

• Kia Diagnostic System (KDS): This diagnostic tablet is essential for performing the software upgrade. No specific part number is listed, but it is a required tool.
• VCI-II: The Vehicle Communication Interface is used to connect the KDS tablet to the vehicle's ECU. No specific part number is listed.
• Vehicle Emissions Recall Proof of Correction Card (Part Number: UT161 SC340): Required for specific states to document the completion of the emissions-related service.
• Campaign Completion Label (Part Number: UT160 SC340): Applied under the hood to indicate the campaign has been performed.

Owner Action

If you own a 2014-2021 Kia Optima, Sorento, or Sportage with a 2.4L Theta II GDI engine, it is recommended to contact your authorized Kia dealership to schedule this voluntary emissions service campaign. The software update is performed free of charge. Your dealer can check your vehicle's VIN to confirm if it is affected by the SC340 campaign and arrange for the necessary ECM software upgrade. This ensures your vehicle complies with emissions standards and benefits from improved diagnostic capabilities.

Warranty Information

This service campaign is covered under specific warranty codes. For claim submission procedures, Kia retailers should refer to Warranty Bulletin 2025-28. The warranty information for this Kia Theta II ECM Logic Improvement includes:

• N Code: N99
• C Code: C99
• Claim Type: R (Recall/Service Action)
• Repair Description: (SC340) 2.4L GDI Theta II Emissions Logic Improvement
• Labor Operation Codes: 250067R1, 250A21RO, 250A21R1, 250067RO (specific codes apply based on model year and configuration, e.g., 250067R1 for JF 18MY, 250A21RO for JFa 18-20MY, 250A21R1 for UMa 18-20MY, 250067RO for QL 18MY and QL 19-22MY).
• Operation Time: 0.3 M/H (Man-Hours) for most models. For 16-17MY JF, JFa, UMa, QL models, the software release is TBD, and labor time is also TBD M/H.
• Replacement Part Number: N/A (software update).

VIN inquiry data for this repair is provided for tracking purposes only. Kia retailers should reference SC340 when accessing the KDealer+ system. For substitute transportation policy, technicians should refer to the Service Policy and Procedures Manual (SPPM) 6.11 “Kia Substitute Transportation.”

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Source: NHTSA ID: 11026533