Recall 22V553 covers 71 2023 Thomas Built Buses Saf-T-Liner Hdx and Saf-T-Liner C2 school buses for ECM short circuits. Free repair once available.
Thomas Built Buses is recalling 71 2023 Saf-T-Liner Hdx and Saf-T-Liner C2 school buses because the engine control module can short circuit and shut the engine down without warning. An unexpected shutdown raises crash risk and can force a bus evacuation in traffic; the dealer repair will be free once Thomas Built Buses makes it available.
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What's wrong?
The engine control module on these 2023 Thomas Built Buses Saf-T-Liner Hdx and Saf-T-Liner C2 school buses is the computer that manages engine operation. It reads signals from the engine, controls fuel and timing, and keeps the engine running as the driver expects. Inside that module, the printed circuit board carries electrical signals between the module's components.
The defect is in certain printed circuit boards supplied through Cummins. During manufacturing, a loose screw in a soldering fixture placed extra force on a capacitor and the circuit board. Over time, movement inside the board can wear through an insulating layer and create high current draw. When that happens, the engine control module can lose communication and the engine can shut down unexpectedly.
There is no warning sign before failure. While driving, the bus can stall without advance notice, and the engine can fail to restart after the shutdown.
Who's affected?
The Saf-T-Liner Hdx and Saf-T-Liner C2 share the same engine printed circuit board issue in the engine control module.
| 2023 Thomas Built Buses Saf-T-Liner Hdx | Engine control module (ecu/ecm) |
|---|---|
| 2023 Thomas Built Buses Saf-T-Liner C2 | Engine control module (ecu/ecm) |
| Units affected | 71 |
| Field incidents | NHTSA has logged 10 field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific bus.
What's the safety risk?
An unexpected engine shutdown raises crash risk and can leave a school bus disabled in traffic, where evacuation adds injury risk for passengers. There is no warning sign before failure. Report any stall or no-restart condition to the dealer before returning the bus to route service. Repair will be free at any franchised Thomas Built Buses dealer once available.
What should I do?
- Check your VIN to confirm your 2023 Thomas Built Buses Saf-T-Liner Hdx or Saf-T-Liner C2 is included in this recall.
- Use the Thomas Built Buses owner notice for the current repair instructions before scheduling service.
- Call Thomas Built Buses customer service at 1-800-547-0712 with questions and reference recall number 22V553 when you call.
- Contact a franchised Thomas Built Buses dealer when repair instructions are available to schedule the free ECM replacement that addresses unexpected engine shutdown.
- Plan bus routes and service use around the shutdown risk until the ECM repair is complete.
What happens at the repair
Because the final repair is still under development, do not treat this as a repair that can be scheduled yet. Once it opens, a Thomas Built Buses technician will replace the engine control module, or ECM, at no charge under the recall. The ECM is the computer that controls engine operation, so the repair focuses on replacing that module rather than adjusting a driver setting. For prior ECM related repairs not covered by the manufacturer's limited warranty, DTNA says a recall specific reimbursement plan will be provided. Keep repair invoices and warranty paperwork for the service desk.
| Reimbursement | Reimbursement available |
|---|
Timeline
| July 29, 2022 | NHTSA published the recall |
|---|---|
| September 26, 2022 | Dealer notification began |
| September 26, 2022 | Dealer notification ended |
| September 26, 2022 | Interim owner notification (was planned for this date) |
| September 27, 2022 | Owner notification mailed |
Frequently asked questions
What is recall 22V553?
Recall 22V553 covers 71 2023 Thomas Built Buses Saf-T-Liner Hdx and Saf-T-Liner C2 school buses. The engine control module can short internally and shut the engine down unexpectedly. Cummins will replace the ECM for free.
What should I do if my 2023 Thomas Built Buses Saf-T-Liner Hdx or Saf-T-Liner C2 is on this recall?
Check your VIN to confirm your specific bus is included in recall 22V553. If it is, contact a franchised Thomas Built Buses dealer or DTNA customer service at 1-800-547-0712 and reference recall FL-949. Ask whether the ECM replacement is ready for your bus.
Is the recall repair free?
Yes. Federal recall law requires the safety recall repair at no cost, and the recall remedy says Cummins will replace the engine control module free of charge. Parts and labor are covered for included buses.
What is the safety risk?
The safety risk is an unexpected engine shutdown while the school bus is in use. That can increase crash risk. A disabled school bus can also force an evacuation in uncontrolled traffic, increasing injury risk for passengers.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/22V553000 |
|---|---|
| Thomas Built Buses customer service | 1-800-547-0712 |
| NHTSA recall # | 22V553 |
| NHTSA recall # (full) | 22V553000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Misc. Document (PDF)
- Download Recall Report (PDF)
- Download Owner Notice (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 20, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →