Two problems related to software have been reported for the 2013 Mazda MAZDA3. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2013 Mazda MAZDA3 based on all problems reported for the 2013 MAZDA3.
While coasting, application of the brakes will make the headlights flicker. An ecu voltage monitor registers a drop in the voltage that lasts for as long as the headlights flicker which is approximately 3 seconds. Mazda is aware of this problem and apparently a software update to the ecu will solve it. They offered this for free under the 6yr/60k mile warranty but apparently did not tell their customers.
Pcm does not regulate alternator output correctly causing the headlights to flash/strobe and horn tone to fluctuate while braking in motion. The headlights flashing could lead other drivers to believe you are signaling them, and lack of power to horn reduces the audibility and may not be heard by other drivers. Dealership/Mazda is aware of the issue and has provided a "software update" to fix the issue, but has not issued a recall, thus requiring consumers to pay $60-$100 usd for the update if out of warranty. On November 22th 2017 I was approaching an intersection and was braking coming to the red light when a vehicle on a side street waved at me and pulled out in front of me I used my horn of which fluctuated with power, I was able to avoid the crash but it was a close call. I suspect the other vehicle thought my flashing headlights were signaling them to "go ahead". I believe this needs to be a recall as this issue has the potential to cause serious injury or loss of life.