P103B on the 2021 Mack LR
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.
| CBR-2303 202307 | 2023-08-02. Service bulletin. CBR: Mack DEF Dosing Valve Diagnostic Trouble Codes (DTC) P202D00, P208E00, P103B00 - US10+OBD13 And Newer Emissions |
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1 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.