2023 Thomas Built Buses Saf-T-Liner Hdx problems, complaints & recalls
Safety recalls (8)
Engine And Engine Cooling:cooling System:hoses/Lines/Piping/Fittings 2026-02-13 · campaign 26V086000 · 2,843 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain Thomas Built Buses 2023-2026 Saf-T-Liner EFX and Saf-T-Liner HDX school buses. The heater hose clamps may not have been tightened properly, causing the hose to disconnect and leak heating coolant inside the passenger compartment.
Risk: Contact with hot heating coolant may burn occupants, increasing the risk of injury.
Fix: Dealers will inspect and replace the heater hose clamps, as necessary, free of charge. Owner notification letters were mailed April 10, 2026. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is F1030.
Engine And Engine Cooling:cooling System:hoses/Lines/Piping/Fittings 2026-02-13 · campaign 26V087000 · 52 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain Thomas Built Buses 2023-2025 Saf-T-Liner EFX and 2023-2026 Saf-T-Liner HDX vehicles. The heater hose clamps may not have been tightened properly, causing the hose to disconnect and leak heating coolant inside the passenger compartment.
Risk: Contact with hot heating coolant may burn occupants, increasing the risk of injury.
Fix: Dealers will inspect and replace the heater hose clamps, as necessary, free of charge. Owner notification letters were mailed April 10, 2026. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is F1030.
Structure:body:roof And Pillars 2022-10-12 · campaign 22V762000 · 17,613 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain 2011-2023 Thomas Built EFX and HDX school buses. The exterior roof panel was manufactured with insufficient joint strength. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 221, "School Bus Body Joint Strength."
Risk: A school bus exterior roof panel with insufficient joint strength may separate during a crash, increasing the risk of injury.
Fix: Dealers will add additional mechanical fasteners to secure the joints, free of charge. Owner notification letters were mailed June 2, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL957.
Structure:body 2022-09-14 · campaign 22V688000 · 1,259 vehicles
Defect: Daimler Trucks North America LLC (DTNA) is recalling certain 2020-2023 Thomas Built Saf-T-Liner HDX school buses. The rear exterior side-body panel was manufactured with insufficient joint strength. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 221, "School Bus Body Joint Strength."
Risk: A school bus panel with insufficient joint strength may separate during a crash, increasing the risk of injury.
Fix: Dealers will add additional mechanical fasteners to secure the joints, free of charge. Owner notification letters were mailed November 11, 2022. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall FL953.
Engine And Engine Cooling:engine:engine Control Module (Ecu/Ecm) 2022-07-29 · campaign 22V553000 · 71 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain 2023 Thomas Built Saf-T-Liner HDX and Saf-T-Liner C2 school buses. The engine control module (ECM) may experience an internal short-circuit, which can result in an unexpected engine shut down.
Risk: Unexpected engine shut down can increase the risk of a crash. Additionally, a disabled school bus may require an evacuation procedure in an uncontrolled traffic situation, increasing the risk of injury to passengers.
Fix: Cummins will replace the ECM, free of charge. Owner notification letters are expected to be mailed September 26, 2022. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-949.
Seats:mid/Rear Assembly 2022-07-19 · campaign 22V510000 · 1,806 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain 2014-23 Thomas Built Buses HDX and 2014-22 EFX school buses equipped with 39-inch S3C seat frames and 3-point flex seatbelts. The passenger seat frames may crack and rotate from fatigue.
Risk: Cracked passenger seat frames may not adequately secure passengers in the event of a crash, increasing the risk of injury.
Fix: Dealers will secure the seat frames with brackets, free of charge. Owner notification letters were mail December 4, 2023. Owners may contact DTNA's customer service at 1-800-547-0712. DTNA's number for this recall is FL946.
Electrical System:12v/24v/48v Battery:cables 2022-04-22 · campaign 22V271000 · 2,943 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain 2019-2023 Thomas Built Bus HDX school buses. The positive battery cable may be routed improperly, allowing it to chafe against the transmission oil cooler hoses, which can cause an electrical short circuit.
Risk: An electrical short circuit can increase the risk of a fire.
Fix: Dealers will inspect and repair the cable routing, as necessary, free of charge. Owner notification letters were mailed January 20, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL928.
Electrical System:12v/24v/48v Battery:cables 2022-04-22 · campaign 22V272000 · 138 vehicles
Defect: Daimler Trucks North America, LLC (DTNA) is recalling certain 2019-2023 Thomas Built Bus HDX commercial buses. The positive battery cable may be routed improperly, allowing it to chafe against the transmission oil cooler hoses, which can cause an electrical short circuit.
Risk: An electrical short circuit can increase the risk of a fire.
Fix: Dealers will inspect and repair the cable routing, as necessary, free of charge. Owner notification letters were mailed January 20, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL929.
Service bulletins (26)
Technical service bulletins are repair instructions manufacturers send dealers for known issues. Unlike recalls, the fix is not automatically free — but naming the bulletin at the service desk can save diagnosis time and support goodwill repairs.
Unknown Or Other 2026-07-06 · TSB-54-029-FTL · Service Bulletin/Repair Instructions
technical service bulletin for electrical wiring modifications for type dfootwell heater
Engine 2026-04-23 · SS 306-TBB · Other
service solution for hdx def header service replacement additional parts
Electrical System 2026-03-20 · SS 308-TBB · Other
service solution for timer relay tbb 202400 replacement
Unknown Or Other 2025-09-09 · MYCOM_09092025-1 · Other
my communications for dtna announces extended coverage policy updates
Engine 2025-08-07 · SS306-TBB · Other
service solution for hdx def header service replacement additional parts
Unknown Or Other 2025-06-17 · SS1033857-TBB · Other
service solution for floor covering bubbles
Showing the 6 most recent of 26 bulletins. Search all of them free at nhtsa.gov.
What owners report
No detailed complaint narratives on file.
Excerpts of consumer complaints filed with NHTSA, lightly truncated. They are owner statements, not verified findings.