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Dead battery Mazda 3

Dead battery Mazda 3 — Service bulletin Mazda 3

Mazda has issued a service bulletin #01-010/20 to address a Mazda 3 dead battery situation on the vehicles listed below. The bulletin talks about a situation where the Mazda 3 battery dies if the vehicle is parked for more than 8 hours.

Vehicles affected by service bulletin #01-010/20

2019- 2020 Mazda3 (Japan built) with VINS lower than JM1BP****** 176445 (produced before April 17, 2020)
2019- 2020 Mazda3 (Mexico built) with VINS lower than 3MZBP****** 140711 (produced before June 12, 2020)
2020 CX-30 with VINS lower than 3MVDM****** 140313 (produced before June 28, 2020)

Mazda reports that the vehicles won’t start because the battery is discharged after the vehicle is parked for more than 8 hours. The cause may be one of the following:

•  The vehicle control system may not have gone to sleep. This can happen if you leave the key fob in the vehicle after the ignition switch was turned off and the doors are closed. This is caused by a software issue in the body control module (BCM) that allows a higher parasitic draw (approx. 6A) to continue for approximately 6 minutes until the vehicle control system goes into sleep mode. If the doors are operated frequently for car washing or luggage loading/unloading etc., it prevents the vehicle control system from sleeping during that time.

•  The parking lights may have been left on because the warning sound for lights on is a short ding, and it may not be noticed.

• The heater control unit may not have gone to sleep because the hazard warning switch was pressed after the ignition was turned off. This is caused by improper control logic of the heater control unit.

Fix for Mazda 3 dead battery

The BCM must be reflashed with new software to shorten the time until going into the sleep mode to approximately 2 minutes.

The software update is not free. It can be done at the dealer or any shop that has the ability to perform reprogramming.

© 2020 Rick Muscoplat

Posted on by Rick Muscoplat


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