Mazda Hit with Software Irregularities in Japan, Halts Sales and Vows Transparency

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Mazda has encountered a bump in the road for some of its vehicles sold in Japan. The issue stems from irregularities discovered during the certification process for two models: the MX-5 Miata RF and the Mazda2. Additionally, concerns have been raised regarding crash test procedures for the Mazda6/Atenza and previous-generation Mazda3/Axela.

The heart of the matter lies in the engine control software used for the MX-5 Miata RF (the hardtop convertible version). During the certification process, Mazda admits to using a different software version compared to the one installed in production cars delivered to customers. This software had a partially deactivated ignition timing adjustment function. This raises concerns about the accuracy of the reported engine performance data submitted for certification.

The impact of this software discrepancy is significant. From June 2018, over 10,000 MX-5 Miata RFs with the potentially inaccurate software rolled off the production line. The vast majority, exceeding 10,700 units, have already been delivered to Japanese customers. It's important to note that this issue is specific to the 2.0-liter engine found exclusively in the RF version. The soft-top Miata, available with a smaller 1.5-liter engine, is unaffected.

Mazda has taken swift action to address the situation. Recognizing the importance of transparency and customer satisfaction, they have halted further deliveries of the MX-5 Miata RF in Japan as of May 30th. They are diligently working on a revised engine control software version for testing that accurately reflects the software used in customer vehicles. This ensures a fair and accurate representation of the car's performance.

The issue extends beyond the MX-5 Miata RF. A similar software irregularity has been identified in the Mazda2 hatchback equipped with the 1.5-liter engine. Here, the number of affected vehicles is considerably higher, with over 42,000 units produced since June 2021. Fortunately, the vast majority (over 41,000) remain unsold, allowing Mazda to rectify the software issue before reaching customers.


While the engine software discrepancies are concerning, a separate issue has been identified concerning crash test procedures for the Mazda6/Atenza and previous-generation Mazda3/Axela. During frontal collision tests, an "external device" was used to trigger the airbag deployment instead of relying on the car's onboard sensors. This raises questions about the validity of the crash test results and the cars' actual safety performance in real-world scenarios.

However, Mazda emphasizes that all affected vehicles are safe to drive. They have discontinued the use of this irregular hardware in production and assure owners that their cars meet all safety standards.

These irregularities came to light following a request by the Japanese Ministry of Land, Infrastructure, Transport and Tourism in late January 2024. It's worth noting that this incident follows a similar scandal involving Toyota and Daihatsu in 2023 concerning substandard crash test procedures. Mazda's commitment to transparency and their prompt corrective actions are crucial in regaining consumer trust and ensuring the safety and proper performance of their vehicles.

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