MAZDA
01-001-26a
Manufacturer communications
- Publication date
- 2026-01-31
- Received by NHTSA
- 2026-02-03
- NHTSA record numbers
- 11028092
Manufacturer summary
Original wording in English
Some customers may experience a check engine light ON with DTC P0126:00 (Thermostat stuck open) and one or more of the following symptoms: Engine takes longer to warm up.
• Engine temperature gauge fluctuates.
• Low coolant temperature indicator (blue) light stays on longer or turns on while driving.
• Poor heater performance, especially at idle.
• This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
• Engine temperature gauge fluctuates.
• Low coolant temperature indicator (blue) light stays on longer or turns on while driving.
• Poor heater performance, especially at idle.
• This concern may be caused if the coolant control valve fail-safe thermostat opens at a temperature lower than the normal temperature due to a deformation of the thermostat diaphragm. To eliminate the concern, the water flow control valve specification has been modified.
Reported code forms
Check vehicle applicability
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| Make | Model | Model year |
|---|---|---|
| Mazda | CX-3 | 2021 |
| Mazda | CX-3 | 2020 |
| Mazda | CX-3 | 2019 |
| Mazda | CX-30 | 2023 |
| Mazda | CX-30 | 2022 |
| Mazda | CX-30 | 2021 |
| Mazda | CX-30 | 2020 |
| Mazda | CX-5 | 2025 |
| Mazda | CX-5 | 2024 |
| Mazda | CX-5 | 2023 |
| Mazda | CX-5 | 2022 |
| Mazda | CX-5 | 2021 |
| Mazda | CX-5 | 2020 |
| Mazda | CX-5 | 2019 |
| Mazda | CX-5 | 2018 |
| Mazda | MAZDA3 | 2023 |
| Mazda | MAZDA3 | 2022 |
| Mazda | MAZDA3 | 2021 |
| Mazda | MAZDA3 | 2020 |
| Mazda | MAZDA3 | 2019 |
| Mazda | MAZDA6 | 2021 |
| Mazda | MAZDA6 | 2020 |
| Mazda | MAZDA6 | 2019 |
| Mazda | MAZDA6 | 2018 |