2019–2021 Thomas Built Buses Saf-T-Liner C2 Recall: Engine control module software may be calibrated incorrectly, causing the…
NHTSA campaign 21V120000 · Engine and Engine Cooling · filed Feb 25, 2021 · verified Jul 30, 2026
The defect
Daimler Trucks North America, LLC (DTNA) is recalling certain 2019-2021 Thomas Built Buses Saf-T-Liner C2 school buses equipped with Cummins B6.7N engines. The engine control module software may be calibrated incorrectly, causing the engine to not limit engine speed or torque as intended for certain safety-related functions such as vehicle braking, traction and stability control, speed control, or collision avoidance.
The risk
If safety-related functions such as vehicle braking, stability, speed, and collision avoidance do not function properly, it can increase the risk of a crash.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →The fix — what to do
DTNA will work with the engine manufacturer Cummins Inc. to notify owners, and Cummins dealers will recalibrate the engine control module, free of charge. Owner notifications were mailed on March 29, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA number for this recall is FL-879.
Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.safercar.gov.
Affected vehicles
| Make | Model | Model years |
|---|---|---|
| Thomas Built Buses | Saf-T-Liner C2 | 2019, 2020, 2021 |
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All Thomas Built Buses Saf-T-Liner C2 recalls → · All Thomas Built Buses recalls →
Source: NHTSA recall database, campaign 21V120000 (manufacturer number FL-879). Data last verified Jul 30, 2026.