Service bulletins for the 2020 Mazda CX-9
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
327 on file from NHTSA, as of 2026-10-19.
About P0301 on the 2020 Mazda CX-9: what the code means, and the bulletins and recalls about the same components.
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Only bulletins with trouble code: P0301 are shown. Show all
| 01-001-23a | 2023-03-03. Service bulletin. ENGINE AND ENGINE COOLING. Some customers may complain about a poor acceleration and rough idling or the CHECK ENGINE light ON with DTC P0301:00, P0302:00, P0303:00, P0304:00.NOTE: Only turbo engines are applicable; non-turbo engines are NOT applicable. In most cases, DTCs P030X stores, but sometimes not. Sometimes the CHECK ENGINE light does not recognize this engine concern. This is caused by the variable valve in the exhaust manifold seizing and causing the exhaust port to become hot and the exhaust valve seat to wear unevenly, resulting in compression leakage. To eliminate this concern, the design of the exhaust manifold has been modified. |
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The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.