P0400 on the 1996 Mazda Protege
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.
| 97083001897 | 1998-03-30. Service bulletin. UNDER CERTAIN LOAD AND RPM RANGES EXCESSIVE NOISE MAY BE IN GENERATED IN THE EGR BOOST SENSOR CIRCUIT CAUSING DTC P0400 TO BE SET. *YC |
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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.