This bulletin applies to 2024-2025 Mazda CX-90 PHEV vehicles built before March 1, 2025, 2025 CX-70 PHEV vehicles built before March 1, 2025. Some vehicles may exhibit a check engine light on at engine startup, with DTC P0531:00 stored in memory (refrigerant pressure sensor No. 1 system: function malfunction).

This is caused by improper control logic of the PCM and the dash electrical supply unit (Dash-ESU). The control logic has been modified. Reprogram the PCM and Dash-ESU with the latest software.