Inaccurate Fuel Gauge Reading

Affected vehicles (2)

Component / system

Defect

Mazda North American Operations (Mazda) is recalling certain 2024-2025 CX-90 and 2025 CX-70 mild hybrid electric vehicles (MHEV). The fuel gauge in the instrument cluster may display an inaccurate fuel reading.

Risk / consequence

An inaccurate fuel gauge may result in the vehicle unexpectedly running out of fuel and stalling, increasing the risk of a crash.

Remedy

Dealers will update the body control module (BCM) software, free of charge. Owner notification letters were mailed October 24, 2025. Owners may contact Mazda customer service at 1-800-222-5500 Option 6. The manufacturer's number for this recall is 78251. The information in your report suggests that Mazda may have been aware of this issue more than five business days before filing a report with NHTSA. Please be reminded that under Federal law, this agency is to be notified of all safety defect and/or noncompliance decisions within five business days. 49 CFR 573.6 Significant civil penalties can be assessed for this violation.

Chronology of events

1. September 2023

   September 2023: The sub-tank sending unit was recovered and inspected, revealing that the root cause was a decrease in gauge resistance caused by unintended conductivity occurring outside the normal operational range. Since the exact failure mechanism could not be identified, further investigations were initiated to understand why this phenomenon was occurring and to determine the contributing factors.

2. November 2023

   November 2023: The investigation continued but shifted focus, as the occurrences appeared to be specific to the U.S. and Canadian markets.

3. November 2024

   In 2023, three field reports and three warranty claims were received from the U.S. and Territories markets. March ~ November 2024: A more detailed investigation was launched to better understand the region- specific nature of the root cause. Findings indicated that the failure occurred under varying conditions and involved complex chemical reactions influenced by internal temperature of the fuel tank. In parallel with the detailed investigation, countermeasure studies were initiated focusing on improvements to the control logic governing fuel gauge operation.

4. December 2024

   December 2024: The investigation and development of enhancements to the fuel gauge operation control logic was successfully completed, incorporating findings from the investigations. These improvements were designed to enhance the accuracy, reliability, and responsiveness of the fuel gauge across a broader range of operating conditions.

5. In 2024, six field reports and twenty-six warranty claims were received from the U.S. and Territories markets.

6. January 2025

   January 2025: The root cause of the decreased resistance value in the sub-tank sending unit was determined to be a reaction between fuel containing ethanol and materials on the sending unit circuit board. Over time, this reaction can create a buildup that interferes with the gauge’s ability to measure fuel levels accurately, which may cause the fuel gauge to show an incorrect amount of fuel. February ~ April 2025: Mazda conducted performance, reliability, and robustness evaluations of the improved fuel gauge control logic to ensure consistent functionalities under diverse operating conditions and long-term durability.

7. April 2025

   April 2025: Mazda implemented mass production changes to enhance the fuel gauge operation control logic. These improvements ensure accurate display of the remaining fuel, even when unintended conductivity causes the sub-tank fuel gauge to fluctuate. The updated logic monitors and corrects the resistance value by determining remaining fuel volume in the sub-tank, enabling precise calculation and reliable display of the remaining fuel on the instrument cluster.

8. Jul 28, 2025

   July 28, 2025: Mazda assessed the potential risk associated with this issue, including impact on vehicle operation and customer safety, and defined the scope of the affected range to better understand the overall extent of the concern. As a result, this issue was escalated for evaluation as a potential safety concern.

Notification schedule

Dealer notification

Sep 05, 2025 - Sep 05, 2025 No Dealers

Owner notification

Nov 01, 2025 - Nov 01, 2025 Phased Recall