P0401 on the 2018 Mazda CX-9
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.
| SA-072-17 | 2021-03-08. Service bulletin. If you receive a customer complaint of a Check Engine Light on with a DTC P0401 stored in memory, follow the repair procedure below. |
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| 01-017-18-3518 | 2018-10-09. Service bulletin. Some customers may experience a check engine light on and DTC P0401:00 stored in memory without any drivability issues. P0401:00 - [PCM] EGR flow insufficient detected. This concern may be caused by the detection logic for the DTC is too sensitive. To eliminate this concern, the control logic of the PCM has been modified. |
2 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.