[ASH8]

Those owners who have a TCU Telematics Control Unit also have a Battery Drain issue with eSIM telco mainly in USA (NA0*) cars..

The Fix is now out for 2021 CX-5 and CX-9 with TCU Firmware update 10020 and soon for CX-30 and Mazda 3, this is in addition to the battery drain with key fob module MDARS update.

This TCU Firmware update TCU_7000T11-0*01_8014.kwi appears to fix this TCU issue.
This TCU Firmware update is Model and Region Specific.

 

[ASH8]

I had the battery warning multiple times within the first week of ownership until I read to leave the car locked and ensure the key fobs are located more than 15 feet away from the car. I keep mine in the house in a different room now. I used to have them hanging from the wall just inside the garage entry to the house - a total of about 10'. I haven't had any other issues.

Good to hear and precisely what I wrote months ago, you must have Key Fob at least 10 feet away from car or else it never goes to sleep, I believe the MDARS update shortened the original factory distance (not certain though).

 

[ASH8]

• Multiple times either in my garage or after a 6 hour drive... seems after i open / close the trunk or doors 3/4 times or if i leave the car alone for a day or two... i get this alarm.
• Low battery 12v error telling me to start the car
• 2021 Turbo Premium
• Car still started
• Not yet
• Unsure

This really stinks just knowing i have to be cautious and make sure i start the car often, or that i don't open a door too much :/. I'm not doing anything crazy like listening to the radio, leaving lights on, etc.... just packing and unpacking the car.... and i can't even do that without getting a warning. I've driven it about 1.3k so far and this happens almost every trip.

Contact your DEALER there is a MDARS Software update for Battery Drain issues, Mazda are well aware of issues, there are a few different ones including TCU or telemetry unit software update for Remote App Access with Telcos, discuss with Dealer, there are Bulletins about Drain issue and a fix.

 

[ASH8]

Hi owners, just be aware that any software updates are done from Mazda Japan via MDARS software that your Dealer uses on your car.

MAZDA Motors Europe or UK or Mazda Australia or MNAO never knows of any updates until they recieve the Bulletin or workaround from Japan, The Mazda Dealer knows even less as they rely on Distributors to inform them the Dealer via said TSB.
Distributors and Dealers do not write computer code to rectify problems, all MDARS updates come out of and directly from MC Japan.

While it may be an inconvenience most issues gets resolved completely (in time). Always, Always make sure your Mazda Dealer records your issues no matter what they are on your Repair Order before you sign cars Repair Order. That way records prove of your problem.

Plus also remember Never to a Dealer use hearsay or you read here in this forum to report a problem with your car or you heard of a computer update as most will not act on it.
Mazda Japan and Distributors expect you the owner to directly tell Dealer what your problem actually is in your words, the Dealer reports the Cause once he has fixed issue.

 

[ASH8]

Also, not all TSBs apply worldwide and then you have model year of CX-30 where there are also differences or incompatibility also particularly VIN dates and times.