P0400 on the 2019 Subaru Legacy
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.
Nobody has written a description of this code yet.
| 11-200-20R | 2020-06-02. Service bulletin. This bulletin announces the availability of reprogramming files to optimize the Engine Control Module (ECM) for hard starting in sub-freezing temperatures, DTC P0400, and surging in high altitudes. |
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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.