This bulletin applies to 2020-2021 Mazda CX-30 vehicles built before Jan. 19, 2021, 2019-2021 Mazda3 (Japan built) produced before Dec. 25, 2020, and 2019-2021 Mazda3 (Mexico built) produced before Dec. 29, 2020.
Some customers may complain about brake concerns when coming to a stop while following a vehicle ahead using MRCC (Mazda Radar Cruise Control with Stop and Go function). Concerns may include harder braking at slow speeds just before a complete stop, the vehicle creeps toward the vehicle in front before coming to a complete stop and the “Depress Brake Pedal” warning may appear in the instrument cluster.
This is caused by improper control software of the DSC HU/CM. To eliminate the concern, software of the DSC HU/CM has been modified. Reprogram the DSC with the Mazda Modular Diagnostic System (M-MDS), using the Mazda diagnostic and repair software (MDARS). After reprogramming, pending DTC P2610:00 may be stored in the PCM without the check engine light on. Since this DTC may turn to a current DTC depending on operations after the reprogramming, clear the DTC after all repair work has been done.
If DTC U2120:00 and/or U2500:82 are stored and the i-ACTIVSENSE amber warning light turn on after reprogramming, refer to SA-043/20. If the Welcome lamp function is accidentally activated while using MDARS, it may also cause this concern. Refer to SA-054/20.
Clear the DTC, turn the ignition off and exit the vehicle. Close and lock the driver's door. Wait for at least 10 minutes. Verify the repair by starting the engine and making sure that the check engine light is off and no abnormal warning lights are on.
CALIBRATION
Model File name
2019-2020 Mazda3......................BCKA-4300F-F
2021 Mazda3...............................BFVV-4300F-C
2020 CX-30.................................DFT5-4300F-F
2021 CX-30.................................DEJW-4300F-B
