2020–2021 Gillig Low Floor Recall: Engine calibration software's management of the injection of Diesel…
NHTSA campaign 21V538000 · Engine and Engine Cooling · filed Jul 15, 2021 · verified Jul 30, 2026
The defect
Gillig, LLC (Gillig) is recalling certain 2020-2021 Low Floor vehicles equipped with Cummins L9 Diesel Engines. The engine calibration software's management of the injection of Diesel Exhaust Fluid can allow excessive ammonia into the tailpipe exhaust.
The risk
Exposure to high levels of ammonia can increase the risk of injury.
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
Cummins will recalibrate the engine, free of charge. Owners may contact Gillig's customer service at 1-510-264-5073 or 1-800-735-1500.
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.nhtsa.gov.
Affected vehicles
Related recalls
More Gillig Low Floor recalls
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Other campaigns involving Gillig vehicles
Source: NHTSA recall database, campaign 21V538000. Data last verified Jul 30, 2026.