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NHTSA campaign 21V538000

Gillig Recall 21V-538: Excessive Ammonia in Tailpipe Exhaust

NHTSA recall 21V538000 was reported by Gillig, LLC on July 15, 2021, with 78 vehicles potentially affected (per NHTSA). NHTSA's record lists the Gillig Low Floor for model years 2020–2021. Owners were notified on October 14, 2021, per NHTSA.

Updated daily from NHTSA's recall files

Is my vehicle included?

This page lists, by model year, the vehicles NHTSA's recall record names for campaign 21V538000 in the model years try.vin imports (1995 and later); NHTSA's own record can list more. A model year on the list doesn't mean every vehicle of that year is included, and some may already have been repaired.

To see whether a specific vehicle is included and still needs the repair, enter its VIN at nhtsa.gov/recalls.

Free VIN check: decode a VIN to see its year, make and model.

Key facts

NHTSA campaign
21V538000 (also written 21V-538 or 21V538)
Filed by
Gillig, LLC
Report received
Potentially affected
78 vehicles (per NHTSA)
Component
Engine and Engine Cooling — Exhaust System — Manifold/Header/Muffler/Tail Pipe
Owners notified

Repair completion: 100% (latest rate the manufacturer reported to NHTSA; dataset updated October 21, 2026)

NHTSA cautions against comparing completion rates across recalls or manufacturers. How try.vin reads them.

Vehicles listed for this recall

NHTSA's recall record lists these vehicles for recall 21V538000. try.vin imports model years 1995 and later, so NHTSA's own list can be longer. Model years with a try.vin recall page link to it. Build dates are NHTSA's range for a model year (per NHTSA); a vehicle built in that range is not necessarily included.

Gillig

All Gillig recalls

NHTSA's recall notice

As NHTSA's recall record states it for campaign 21V538000.

Defect description

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.

Safety consequence

Exposure to high levels of ammonia can increase the risk of injury.

Manufacturer remedy

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.

Notes

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.

Sources

Official NHTSA notice for recall 21V538000

Campaign details come from NHTSA's recall files, which try.vin imports once a day. The plain-language subject and the completion rate come from the U.S. Department of Transportation's Recalls Data dataset. How try.vin reads recall data.