NHTSA Service Bulletin 10203301: Cummins B6.7
Official manufacturer communication context for model years not specified Cummins B6.7, with affected products, buyer checks and links into Carchieve recall, problem and VIN research.
Reviewed June 2026 from NHTSA manufacturer communication and service bulletin records. Carchieve is independent and not affiliated with any vehicle manufacturer or government agency.
This Technical Service Bulletin describes the verification and resolution of incorrectly replaced aftertreatment diesel exhaust fluid (DEF) dosing units. Multiple "trouble not found" aftertreatment DEF dosing units have been returned from the field due to being replaced while troubleshooting Fault Codes 3558 and/or 3559. Neither a good or malfunctioning aftertreatment DEF dosing unit can cause Fault Codes 3558 or 3559 to come active as these fault codes are isolated within the OEM wiring harness. This is an update to a previously submitted communication.
What this bulletin may mean before buying
Treat this as service research, not a verdict on one car. Before you buy, compare this communication with official recall campaigns, model-level owner complaint patterns, and the exact vehicle’s VIN-decoded specifications. A bulletin can help you ask a seller or dealer sharper questions about software updates, known repairs, warranty extensions and service history.
Affected products listed in this communication
Buyer checklist
- Run the 17-character VIN and confirm the year, make, model, engine and equipment match the listing.
- Check recall campaign pages for safety actions that may require dealer repair.
- Compare this bulletin with common problem pages for the same model and component area.
- Ask the seller or dealer whether the bulletin procedure, update or inspection has already been completed.
- Use the used-car buying checklist and get an independent inspection.
Frequently asked questions
What is NHTSA service bulletin 10203301?
This Technical Service Bulletin describes the verification and resolution of incorrectly replaced aftertreatment diesel exhaust fluid (DEF) dosing units. Multiple "trouble not found" aftertreatment DEF dosing units have been returned from the field due to being replaced while troubleshooting Fault Codes 3558 and/or 3559. Neither a good or malfunctioning aftertreatment DEF dosing unit can cause Fault Codes 3558 or.
Is a service bulletin the same as a recall?
No. A recall is a safety campaign with a required remedy for affected VINs. A service bulletin or manufacturer communication usually describes diagnostic, repair, software, warranty or service information.
How should a used-car buyer use this bulletin?
Use it as a research signal. Compare it with recalls, owner complaints, service records, a VIN report and an independent inspection before buying.
Check the exact VIN before you buy
Model-level pages show public safety patterns. A full VIN report helps confirm the exact vehicle, decoded specs, recall applicability and buyer checks.
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