Recall 11V172 affects 475 2008-2009 Thomas Built Buses school buses and B2 chassis for engine software shutdown errors. Repair is free through Detroit Diesel.
Thomas Built Buses is recalling 475 2008-2009 Saf-T-Liner C2, Saf-T-Liner Hdx, and B2 school buses and chassis under recall 11V172 because engine software can mishandle aftertreatment fault codes. The defect can trigger an unexpected shutdown or fail to shut down an overheating aftertreatment device, which raises crash and fire risk; the dealer repair will be free once available.
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What's wrong?
The engine software on 2008-2009 Thomas Built Buses Saf-T-Liner C2, B2, and Saf-T-Liner Hdx school buses and bus chassis helps the engine respond to fault codes from the exhaust treatment system. That system manages hot exhaust after it leaves the engine. When the software reads a serious fault code, it decides whether the engine needs a controlled shutdown to protect the vehicle.
On affected buses equipped with EPA 2007 MBE 900 Detroit Diesel engines, the software does not respond correctly to certain exhaust treatment fault codes. It can shut the vehicle down when shutdown is not needed. It can also fail to shut the vehicle down when the exhaust treatment device reports an over-temperature fault.
There is no warning sign before failure. The first thing a driver notices is the wrong shutdown behavior itself: an unnecessary engine shutdown, or no shutdown when the system reports an over-temperature fault.
Who's affected?
Covers three bus models across the 2008 and 2009 model years, all tied to engine and engine cooling.
| 2008 Thomas Built Buses Saf-T-Liner C2 | Engine and engine cooling |
|---|---|
| 2009 Thomas Built Buses Saf-T-Liner C2 | Engine and engine cooling |
| 2009 Fccc B2 | Engine and engine cooling |
| 2008 Fccc B2 | Engine and engine cooling |
| 2008 Thomas Built Buses Saf-T-Liner Hdx | Engine and engine cooling |
| 2009 Thomas Built Buses Saf-T-Liner Hdx | Engine and engine cooling |
| Units affected | 475 |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific bus is included.
What's the safety risk?
An unexpected vehicle shutdown increases the risk of a crash. Aftertreatment overheating without engine shutdown creates a fire risk. If your VIN is included, schedule service promptly and ask the dealer how to handle the bus until repair. Repair will be free at any franchised Thomas Built Buses dealer once available.
What should I do?
- Check your VIN to confirm your 2008-2009 Thomas Built Buses Saf-T-Liner C2, B2, or Saf-T-Liner Hdx is included in this recall.
- Watch for the Thomas Built Buses owner notice before scheduling repairs if your VIN is included.
- Contact Thomas Built Buses customer service at 1-800-547-0712 and reference recall number 11V172 when you call.
- Ask about the Detroit Diesel engine software repair that fixes incorrect aftertreatment fault-code shutdown behavior.
- Bring the recall notice and service records to the repair appointment.
What happens at the repair
At the dealer, a Thomas Built Buses technician handles the recall work with Detroit Diesel for the EPA 2007 MBE 900 engine software. The repair addresses software that can respond incorrectly to aftertreatment device fault codes, including unnecessary shutdown or failure to shut down during an over temperature fault. The source remedy says repairs are performed by Detroit Diesel free of charge, and the safety recall began on March 25, 2011. This campaign also expands prior recall 10V-468.
Timeline
| March 15, 2011 | NHTSA published the recall |
|---|---|
| March 25, 2011 | Owner notification mailed |
Frequently asked questions
What is recall 11V172?
Recall 11V172 covers 475 2008-2009 Thomas Built Buses Saf-T-Liner C2, B2, and Saf-T-Liner Hdx school buses with EPA 2007 MBE 900 Detroit Diesel engines. The engine software does not react properly to certain aftertreatment fault codes. Detroit Diesel performs the repair for free.
What should I do if my 2008-2009 Thomas Built Buses Saf-T-Liner C2, B2, or Saf-T-Liner Hdx is on this recall?
Check your VIN to confirm your specific bus is included in recall 11V172. If it is, contact a franchised Thomas Built Buses dealer or Detroit Diesel service location to arrange the free engine software repair. Reference recall number 11V172 when you call.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the safety defect at no cost, and the recall remedy says Detroit Diesel performs this repair free of charge. Thomas Built Buses owners can also contact Daimler Trucks at 1-800-547-0712 for recall support.
What is the safety risk?
The safety risk is engine software that handles aftertreatment device fault codes incorrectly. NHTSA campaign 11V172 says an unexpected shutdown increases crash risk, while aftertreatment overheating without engine shutdown results in a fire risk. The free repair corrects the software issue.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/11V172000 |
|---|---|
| Thomas Built Buses customer service | 1-800-547-0712 |
| NHTSA recall # | 11V172 |
| NHTSA recall # (full) | 11V172000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Owner Notification Letter (PDF)
- Download Defect / Noncompliance Notice (PDF) (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on June 3, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →