TSB: CHEVROLET SIERRA 1500, SIERRA 2500, SIERRA 3500, SIERRA DENALI, SILVERADO 1500, SILVERADO 2500, SILVERADO 3500, SILVERADO 4500HD, SILVERADO 5500HD, SILVERADO 6500HD (2018–2022)
Bulletin 20NA203 — October 12, 2020
Bulletin Details
| Bulletin ID | 20NA203 |
| Manufacturer | CHEVROLET |
| Models | SIERRA 1500, SIERRA 2500, SIERRA 3500, SIERRA DENALI, SILVERADO 1500, SILVERADO 2500, SILVERADO 3500, SILVERADO 4500HD, SILVERADO 5500HD, SILVERADO 6500HD |
| Model Years | 2018–2022 |
| Date Issued | October 12, 2020 |
| Date Added to NHTSA | June 21, 2022 |
| Component | ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| Vehicles Affected | 180 combinations |
What is a TSB?
A Technical Service Bulletin is a document issued by the vehicle manufacturer to inform dealership technicians about a known issue and the recommended repair procedure. TSBs are not mandatory recalls — they serve as repair guidance for common problems.
If your vehicle has this issue, bring this bulletin ID to your dealer. If under warranty, the repair should be covered at no cost.
Summary
This informational bulletin explains how the regen works for the DEF system and how it works at different levels.
Affected Vehicles
| Make | Model | Year | Component |
|---|---|---|---|
| GMC | SIERRA 1500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 1500 | 2022 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 2500 | 2022 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 3500 | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 1500 | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 2500 | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 3500 | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 4500HD | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 5500HD | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 5500HD | 2022 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 6500HD | 2022 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 6500HD | 2022 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 1500 | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 1500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 1500 | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 2500 | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 2500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 2500 | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 3500 | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 3500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 3500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 1500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 1500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 1500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 2500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 2500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2021 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 3500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2021 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 3500 | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 3500 | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 4500HD | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 5500HD | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 5500HD | 2021 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 6500HD | 2021 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 6500HD | 2021 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 1500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2020 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 2500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2020 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 2500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2020 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 2500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 2500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2020 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 3500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2020 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 3500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2020 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 3500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 3500 | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA DENALI | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 1500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2020 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2020 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2020 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 2500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 2500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2020 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 3500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2020 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 3500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2020 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 3500 | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 3500 | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 4500HD | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 5500HD | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 5500HD | 2020 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 6500HD | 2020 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 6500HD | 2020 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 1500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2019 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 2500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 2500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 2500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 2500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2019 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 3500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 3500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 3500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 3500 | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2019 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA DENALI | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA DENALI | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA DENALI | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA DENALI | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 1500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2019 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 2500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 2500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2019 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 3500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 3500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 3500 | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 3500 | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2019 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 4500HD | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2019 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 4500HD | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 4500HD | 2019 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 4500HD | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 4500HD | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 5500HD | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 5500HD | 2019 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 6500HD | 2019 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 6500HD | 2019 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2018 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 1500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA 1500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 1500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2018 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA 2500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2018 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA 2500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA 2500 | 2018 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA 2500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 2500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA 3500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA 3500 | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2018 | 110000 ELECTRICAL SYSTEM |
| GMC | SIERRA DENALI | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2018 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| GMC | SIERRA DENALI | 2018 | 350000 EQUIPMENT |
| GMC | SIERRA DENALI | 2018 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| GMC | SIERRA DENALI | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| GMC | SIERRA DENALI | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2018 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 1500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2018 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 1500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 1500 | 2018 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 1500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 1500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2018 | 110000 ELECTRICAL SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2018 | 063000 ENGINE AND ENGINE COOLING:EXHAUST SYSTEM |
| CHEVROLET | SILVERADO 2500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 2500 | 2018 | 356000 EQUIPMENT ADAPTIVE/MOBILITY |
| CHEVROLET | SILVERADO 2500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 2500 | 2018 | 350000 EQUIPMENT |
| CHEVROLET | SILVERADO 3500 | 2018 | 061200 ENGINE AND ENGINE COOLING:ENGINE:DIESEL |
| CHEVROLET | SILVERADO 3500 | 2018 | 350000 EQUIPMENT |
Related CHEVROLET Recalls
What Should You Do?
If your vehicle is affected by this TSB, contact your authorized CHEVROLET dealer. Bring this bulletin ID (20NA203) when you visit. If under warranty, the repair should be free. If your warranty has expired, ask about goodwill coverage — manufacturers sometimes cover TSB-related repairs beyond the warranty period.
Frequently Asked Questions
A recall is a mandatory safety fix — the manufacturer must repair every affected vehicle for free. A TSB is an advisory document that describes a known issue and the recommended fix, but repairs are not required. However, some TSBs eventually lead to recalls if the issue poses a safety risk. TSBs are generally issued for quality or performance problems, while recalls address safety defects.
If your vehicle is still under the manufacturer's warranty, TSB-related repairs are typically covered at no cost. If your warranty has expired, you can ask the dealer about goodwill or customer assistance programs. Many manufacturers will cover or partially cover repairs for well-known issues, especially if the TSB was issued recently or affects a large number of vehicles.
Check the make, model, and model year listed above against your vehicle. If they match, this bulletin likely applies. However, TSBs may only affect vehicles with specific production dates, VIN ranges, or configurations. Your dealer can confirm by entering your VIN into their service system, which will show all applicable TSBs and recalls.
This data comes from the National Highway Traffic Safety Administration (NHTSA). Manufacturers are required to submit copies of all communications (including TSBs) sent to their dealers to NHTSA. The agency makes this data publicly available as part of its vehicle safety monitoring program.