Inspecting Mazda fuel trims

    Jan. 30, 2024
    Some Mazda CX-5 models have a MIL on with DTC P0171 (fuel trim too lean) and possibly P030X (misfire).
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    Photo courtesy of Mazda
    If fuel trims are normal after the previous inspections/repairs, the repair is complete. If fuel trims remain abnormal, replace the fuel injectors.
    If fuel trims are normal after the previous inspections/repairs, the repair is complete. If fuel trims remain abnormal, replace the fuel injectors.

    Some 2013-2023 Mazda CX-5, 2016-2022 MX-5, 201202013 Mazda3 Skyactiv, 2014-2023 Mazda3, 2016-2019 CX-9, 2014-2021 Mazda6, and 2016-2019 CX-3 vehicles may experience a MIL on with DTC P0171 (fuel trim too lean) and possibly P030X (misfire).

    Inspect the airbox/filter for proper fitment. Inspect the MAF for correct operation. Inspect the A/F sensor for correct operation. Inspect the fuel trims during normal engine idle conditions.

    If fuel trims are normal after the previous inspections/repairs, the repair is complete. If fuel trims remain abnormal, replace the fuel injectors.

    About the Author

    Motor Age Staff

    Motor Age has been publishing technical content for professional automotive technicians since 1899. Our writers have decades of experience and scores of ASE certifications, and they continue to teach new generations of technicians via classrooms all around the globe, as well as through the books and training manuals they've authored. 

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