Some customers may experience the check engine light on with DTC P0126:00 (Thermostat stuck open) stored
Mazda technical service bulletin 01-006-26 for 2026 Mazda MAZDA3 and 2026 Mazda CX-30.
- Bulletin number
- 01-006-26
- Component
- Unknown or other
- Summary
- Some customers may experience the check engine light on with DTC P0126:00 (Thermostat stuck open) stored. This is due to improper PCM logic control. To eliminate the concern, the PCM control software has been modified. REPAIR PROCEDURE 1. Verify the customer concern. 2. Reprogram the ECU with the Mazda Modular Diagnostic System (M-MDS), using Mazda Diagnostic and Repair Software (MDARS). Refer to MDARS ECU Reprogramming Procedure. NOTE: Be sure to submit Diagnostic Information (ODR) data as it is a required item and will be checked during warranty claim submission. Instructions can be found under M-MDS -> MDARS (Uploading Diagnostic Information (ODR) Data). 3. Clear any other DTCs. 4. Verify the repair by starting the engine (READY ON) and confirming there is no CHECK ENGINE light ON or abnormal warning lights present.
Vehicles covered
- Mazda MAZDA3 2026 2026
- Mazda CX-30 2026 2026
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