P0126 on the 2026 Mazda CX-30
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| DRW59 Warr a | 2026-10-03. Service campaign. Subject: Notification of Dealer Re-Work (DRW59) – 2026MY CX-30 and 2026MY Mazda3 - Check Engine Light On With DTC P0126:00 Dear Mazda Dealer Colleagues, Mazda Motor Corporation has decided to conduct a Dealer Re-Work on certain 2026MY CX-30 and Mazda3 vehicles. Concern Outline: On certain subject vehicles, the check engine light may illuminate with DTC P0126:00 (Thermostat stuck open) stored due to improper PCM control logic. Repair Outline: Reprogram the PCM with the Mazda Modular Diagnostic System (M-MDS), using Mazda Diagnostic and Repair Software (MDARS) by following TSB 01-006/26 repair instructions. ACTION ITEM - STOP DELIVERY: All affected vehicles in inventory can be sold but not delivered until repaired. There are approximately 17,942 new vehicles in dealer stock and/or in transit to dealers. All affected dealer inventory types with this DRW must be repaired prior to delivery. The number of affected units at your dealership can be seen in Inventory & Sales 2.0 in eMDCS and a VIN list (via an internal MNAO campaign reporting) will also be provided to your District Service Manager by 5pm (Pacific Time) on the date this dealer email is sent. Owner Notification: There is no Owner Notification with this or any Dealer Re-Work. PARTS INFORMATION: There are no parts required for this repair. |
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| DRW59 Warranty | 2026-04-04. Service campaign. Subject: Notification of Dealer Re-Work (DRW59) – 2026MY CX-30 and 2026MY Mazda3 - Check Engine Light On With DTC P0126:00 Dear Mazda Dealer Colleagues, Mazda Motor Corporation has decided to conduct a Dealer Re-Work on certain 2026MY CX-30 and Mazda3 vehicles. Concern Outline: On certain subject vehicles, the check engine light may illuminate with DTC P0126:00 (Thermostat stuck open) stored due to improper PCM control logic. Repair Outline: Reprogram the PCM with the Mazda Modular Diagnostic System (M-MDS), using Mazda Diagnostic and Repair Software (MDARS) by following TSB 01-006/26 repair instructions. ACTION ITEM - STOP DELIVERY: All affected vehicles in inventory can be sold but not delivered until repaired. There are approximately 17,942 new vehicles in dealer stock and/or in transit to dealers. All affected dealer inventory types with this DRW must be repaired prior to delivery. The number of affected units at your dealership can be seen in Inventory & Sales 2.0 in eMDCS and a VIN list (via an internal MNAO campaign reporting) will also be provided to your District Service Manager by 5pm (Pacific Time) on the date this dealer email is sent. Owner Notification: There is no Owner Notification with this or any Dealer Re-Work. PARTS INFORMATION: There are no parts required for this repair. |
| DRW59 Repair | 2026-04-04. Service campaign. Subject: Notification of Dealer Re-Work (DRW59) – 2026MY CX-30 and 2026MY Mazda3 - Check Engine Light On With DTC P0126:00 Dear Mazda Dealer Colleagues, Mazda Motor Corporation has decided to conduct a Dealer Re-Work on certain 2026MY CX-30 and Mazda3 vehicles. Concern Outline: On certain subject vehicles, the check engine light may illuminate with DTC P0126:00 (Thermostat stuck open) stored due to improper PCM control logic. Repair Outline: Reprogram the PCM with the Mazda Modular Diagnostic System (M-MDS), using Mazda Diagnostic and Repair Software (MDARS) by following TSB 01-006/26 repair instructions. ACTION ITEM - STOP DELIVERY: All affected vehicles in inventory can be sold but not delivered until repaired. There are approximately 17,942 new vehicles in dealer stock and/or in transit to dealers. All affected dealer inventory types with this DRW must be repaired prior to delivery. The number of affected units at your dealership can be seen in Inventory & Sales 2.0 in eMDCS and a VIN list (via an internal MNAO campaign reporting) will also be provided to your District Service Manager by 5pm (Pacific Time) on the date this dealer email is sent. Owner Notification: There is no Owner Notification with this or any Dealer Re-Work. PARTS INFORMATION: There are no parts required for this repair. |
| DRW59 Dlr Ltr | 2026-04-04. Service campaign. Subject: Notification of Dealer Re-Work (DRW59) – 2026MY CX-30 and 2026MY Mazda3 - Check Engine Light On With DTC P0126:00 Dear Mazda Dealer Colleagues, Mazda Motor Corporation has decided to conduct a Dealer Re-Work on certain 2026MY CX-30 and Mazda3 vehicles. Concern Outline: On certain subject vehicles, the check engine light may illuminate with DTC P0126:00 (Thermostat stuck open) stored due to improper PCM control logic. Repair Outline: Reprogram the PCM with the Mazda Modular Diagnostic System (M-MDS), using Mazda Diagnostic and Repair Software (MDARS) by following TSB 01-006/26 repair instructions. ACTION ITEM - STOP DELIVERY: All affected vehicles in inventory can be sold but not delivered until repaired. There are approximately 17,942 new vehicles in dealer stock and/or in transit to dealers. All affected dealer inventory types with this DRW must be repaired prior to delivery. The number of affected units at your dealership can be seen in Inventory & Sales 2.0 in eMDCS and a VIN list (via an internal MNAO campaign reporting) will also be provided to your District Service Manager by 5pm (Pacific Time) on the date this dealer email is sent. Owner Notification: There is no Owner Notification with this or any Dealer Re-Work. PARTS INFORMATION: There are no parts required for this repair. |
| 01-006-26 | 2026-04-02. Service bulletin. 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. |
| SA-062-25 | 2026-01-03. Service bulletin. Some vehicles equipped with a countermeasure Coolant Control Valve (plug in place of the thermostat inside the CCV) may experience a DTC P0126:00. |
6 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.