2016-2021 Hyundai Theta II Engine Emissions Update (9C2)

Why This Matters

Hyundai has identified that certain 2016-2021 Hyundai vehicles, specifically models equipped with Theta II engines, may exhibit elevated engine-out emissions. These emissions exceed Federal and California standards, which are established to protect public health and welfare from air pollution. This service campaign aims to bring these vehicles into compliance with environmental regulations.

What's Being Addressed

This service campaign, identified as 9C2, focuses on improving the emissions logic within the Engine Control Module (ECM). The primary action is a software update to the ECM, which includes new software events identified as 1367, 1372, and 1373. This update is designed to ensure the vehicle's emissions meet regulatory standards.

Repair Procedure Summary

The repair involves updating the Engine Control Module (ECM) software. Technicians are required to follow the detailed service procedure outlined in Technical Service Bulletin (TSB) 26-01-013H (or its latest version). This procedure includes applying the new software events (1367, 1372, & 1373) and utilizing associated Global Diagnostic System (GDS), Warranty, ROM ID, and Manual Mode Password information.

Technicians performing this update must be Hyundai Certified or hold a higher certification level. After the software update, an emissions sticker (part number NP001-SC9C2) must be applied under the hood. This ensures the Hyundai Theta II emissions update is properly documented.

Required Parts

To complete this service campaign, dealers will utilize specific parts:

• Campaign Sticker: Part Number NP001-SC9C2
• Vehicle Emission Recall - Proof of Correction Card: Part Number NP050-09006 (required for certain states)

Important Warnings and What Owners Should Know

• No Cost to Owners: This service campaign, including the ECM software update and application of the emissions sticker, will be provided at no cost to the customer.
• Alternative Transportation: If your vehicle needs to be kept overnight or for an extended period due to the repair procedure or additional work, the dealership should provide a Service Rental Vehicle (SRC). If an SRC is unavailable, other options such as a 3rd Party Rental or Rideshare may be provided.
• Check Engine Light: If your vehicle experiences a "check engine light" illumination, Hyundai advises reaching out to your nearest Hyundai dealership for assistance to schedule an appointment.
• Proof of Correction: For owners in states that have adopted California emissions regulations (CA, CO, CT, DE, ME, MD, MA, NJ, NY, OR, PA, RI, VT, WA), a "Proof of Correction" certificate (part number NP050-09006) is critical. Retain this certificate for your records, as it may be required when registering your vehicle.

What to Expect at the Dealership

• For Customers with an Appointment: If the service campaign is not part of your originally scheduled services, the dealer will inform you about the open campaign, explaining it requires a software update to the ECM's emissions logic. This service will be provided at no cost, and alternative transportation will be offered if needed.
• For Customers at the Service Lane: If you arrive without an appointment, the dealer will check for open campaigns or recalls and inform you about the necessary ECM software update for emissions logic. This service is free, and alternative transportation will be offered if necessary.
• For Customers Calling: When verifying your appointment over the phone, the dealer can check for open campaigns and inform you if your vehicle requires the ECM software update, which can be addressed during your visit at no cost.

Owner Action

Owners of affected 2016-2021 Hyundai vehicles should expect to be notified via First Class Mail starting in February 2026. Upon receiving notification, it is recommended to schedule an appointment with an authorized Hyundai dealership to have the Engine Control Module (ECM) software updated. This Hyundai Theta II emissions update is essential for maintaining compliance with emissions standards.

Warranty Information

Hyundai will cover the labor for this service campaign. The warranty claim process includes:

• 0.4 M/H for the THETA II ECU Software Update (only when campaign 9C2 is open).
• 0.2 M/H for Administration + Emissions Label Application (only when both campaign 9C2 and 953 are open).

Claims are subject to review after submission. Please note that for digital documentation, a picture of the original shock absorbers displaying their production stamp is required. If the pictures are not compliant with requested ones per TSB, the claim is subject to debit.

TSB History and Revisions

This service campaign references Technical Service Bulletin (TSB) 26-01-013H as the primary document for the repair procedure. This bulletin is a revised version that includes 2016-2017MY Sonata (LFA) and 2017-2018MY Santa Fe Sport (AN) vehicles, along with the new software events (1367, 1372, & 1373).

Previous related bulletins include TSB 25-01-087H-1, posted on December 15, 2025, which covered 2018MY Sonata (LFA) and Tucson (TL) vehicles, and TSB 25-01-087H, published on November 25, 2025.

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Source: NHTSA ID: 11028670