2021 Hyundai Tucson ECU Software Update for Emissions
Hyundai has re-launched Service Campaign 9C2 to address elevated engine-out emissions in certain 2021 Tucson and other Theta II engine-equipped vehicles. This involves an ECU software update detailed in Technical Service Bulletin 26-01-013H-1, which supersedes a previous TSB.
Hyundai Motor America (HMA) has re-launched Service Campaign 9C2 to address a potential issue with elevated engine-out emissions in certain vehicles equipped with Theta II engines. This campaign specifically targets the Engine Control Module (ECM) with a software update. Owners of affected vehicles, including the 2021 Hyundai Tucson, should be aware of this important service action.
This service campaign is detailed in Technical Service Bulletin (TSB) 26-01-013H-1, which provides comprehensive instructions for dealerships to perform the necessary software update. The bulletin was posted on March 5, 2026, and is crucial for ensuring vehicles meet emissions standards and operate optimally.
Why This Update Is Necessary
Certain Hyundai Santa Fe, Santa Fe Sport, Sonata, and Tucson vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. This condition can impact the vehicle's environmental performance and potentially its long-term reliability. The Hyundai Tucson emissions update is designed to recalibrate the ECM to mitigate these elevated emissions.
The Fix: ECU Software Update
The primary remedy for the elevated engine-out emissions is an Engine Control Module (ECM) software update. This update is identified as software event 1383 and involves specific procedures using the Global Diagnostic System (GDS). The update also includes associated Warranty, ROM ID, and Manual Mode Password information for technicians.
Technical Service Bulletin (TSB) 26-01-013H-1 outlines the precise steps for updating the ECM software. This ensures that the vehicle's engine management system is properly calibrated to reduce engine-out emissions. The Hyundai Tucson emissions update is a critical step to maintain compliance and performance.
Important Notes for Owners
After the software update is performed, an Emissions Label will be required for all vehicles. Additionally, a Vehicle Emission - Proof of Correction Card may be necessary, depending on applicable state regulations. Your Hyundai dealer will provide these documents as part of the service procedure.
What Owners Should Do
If you own a 2021 Hyundai Tucson or any of the other models mentioned, it is recommended to contact your authorized Hyundai dealership. They can confirm your vehicle's eligibility for Service Campaign 9C2 by checking your VIN. Once eligibility is confirmed, the dealership will follow the procedures detailed in TSB 26-01-013H-1 to update the ECM software. This Hyundai Tucson emissions update will be performed free of charge under the service campaign.
Superseded Bulletins and Documents
Technical Service Bulletin (TSB) 26-01-013H-1 supersedes the existing TSB 26-01-013H. This update adds the 2015 model year Sonata (LFA) and new software event information. Furthermore, the dealer notification for this campaign also supersedes an existing document, ensuring that dealerships have the most current information for this service action.
Source: NHTSA ID 11029941
Frequently Asked Questions
- What is Service Campaign 9C2?
- Service Campaign 9C2 is a Hyundai initiative to update the Engine Control Module (ECM) software in certain vehicles, including the 2021 Hyundai Tucson, to address elevated engine-out emissions from Theta II engines.
- Which vehicles are affected by TSB 26-01-013H-1?
- While this document specifically links to the 2021 Hyundai Tucson, the campaign also applies to certain 2019-2020 Santa Fe, 2015-2019 Sonata, 2018-2021 Tucson, and 2017-2018 Santa Fe Sport vehicles equipped with Theta II engines. Owners should confirm eligibility with their dealer.
- What is the repair for elevated engine-out emissions?
- The repair involves an ECU software update, identified by software event 1383, which is performed by a Hyundai dealership technician according to the procedures outlined in TSB 26-01-013H-1.
- Will I receive a notification for Service Campaign 9C2?
- Yes, Hyundai Motor America (HMA) has re-launched this Service Campaign with customer notification, so owners of affected vehicles should receive communication regarding this important update.
What Hyundai Tucson owners report
Counted from the records in our database across 22 model years.
- 6,738
- Owner complaints
- 37
- Recalls
- 564
- Service bulletins
- 276
- Crashes reported
- 145
- Fires reported
- 256
- Injuries reported
The 2021 model year
80 complaints, the 18th most of 22 model years on file. Owners reported 2 crashes, 3 fires and 7 injuries for this year, which also has 1 recall on file.
Engine, the system this article covers, accounts for 2,451 of 6,738 complaints (36%), including 39 for 2021.
Complaints by model year
| 2012 | 255 | |
|---|---|---|
| 2013 | 266 | |
| 2015 | 229 | |
| 2016 | 1,626 | |
| 2017 | 1,095 | |
| 2018 | 399 | |
| 2019 | 385 | |
| 2021 | 80 | |
| 2022 | 509 | |
| 2025 | 451 |
Most-reported systems
- Engine — 2,451
- Power Train — 1,273
- Electrical System — 849
- Service Brakes — 761
- Forward Collision Avoidance — 432
Latest recalls for the 2021 model year
- 20V543000 — Service Brakes, Hydraulic (Sep 2020) — Park outside
Recent owner reports about engine
I took my car in to Allen Samuals Hyundai dealership to have the 9C2 recall update completed on May 15th 2026. Ever since then my vehicle has had a rough hesitation or sputtering when driving.
Read owner complaints →Engine knock sensor went off and now the engine needs replacement due to faulty cylinder rod.
Complaints are owner reports filed with NHTSA. They are unverified, and counts depend on how many vehicles were sold, so they are not a failure rate.
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