Service bulletin 08-001-20-3696

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
Type	Service bulletin
NHTSA id	10174574
Published by NHTSA	2020-05-04
Manufacturer's number	08-001-20-3696
Manufacturer's date	2020-04-15
NHTSA component	AIR BAGS:SENSOR:OCCUPANT CLASSIFICATION; ELECTRICAL SYSTEM:12V/24V/48V BATTERY

NHTSA's summary

Some customers may experience the airbag warning light ON with DTC B00A0:09 stored in the SAS control module memory when the battery voltage is low. DTC B00A0:09 (Occupant classification sensor internal signal output unstable). This concern is caused by the low voltage detection time of the occupant classification sensor (OCS) being too short during cranking, which causes detection of the DTC unnecessarily. The concern occurs more often in colder weather when greater electric current is consumed to start the vehicle. To eliminate this concern, the OCS has been modified to avoid unnecessary DTC detection. NOTE: Even if the voltage is recovered after the engine is started, the airbag warning light stays ON during the drive cycle. When the battery voltage becomes stable after the engine is started, the airbag system will operate normally.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Air bags, Electrical system, 12-volt battery

Trouble codes named

B00A0

Vehicles listed
MAZDA CX-3	2016, 2017, 2018, 2019, 2020
MAZDA CX-5	2019, 2020

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
01-007-23	2023-06-04. Service bulletin. The Mazda DCA-8000 is required for all warranty battery testing. If the Mazda DCA-8000 is not used, incorrect battery testing may result in unnecessary battery replacement. Use the following test procedures in this Service Bulletin to test Mazda vehicle batteries and to generate a Warranty Code.
08-002-23	2023-03-03. Service bulletin. Some customers may experience the airbag warning light ON with DTC B00A0:09 stored in the SAS control module memory when the battery voltage is low. DTC B00A0:09 (Occupant classification sensor internal signal output unstable). This concern is caused by the low voltage detection time of the occupant classification sensor (OCS) being too short during cranking, which causes detection of the DTC unnecessarily. The concern occurs more often in colder weather when greater electric current is consumed to start the vehicle. To eliminate this concern, the OCS has been modified to avoid unnecessary DTC detection. NOTE: Even if the voltage is recovered after the engine is started, the airbag warning light stays ON during the drive cycle. When the battery voltage becomes stable after the engine is started, the airbag system will operate normally.
01-006-21-3779a	2021-09-03. Service bulletin. This service bulletin provides testing and charging procedures in order to promote proper battery maintenance, to deliver new vehicles with fully charged batteries, and to reduce unnecessary battery replacement cost. For new vehicles in stock at the dealer, inspect and maintain the battery periodically according to the repair procedure.
15-003-20-3737	2020-10-03. Service bulletin. Some vehicles may exhibit that the SBS/SCBS warning light (amber) turns ON right after the engine is started with DTC U0420:68 [FSC] stored in memory. • DTC U0420:68 [Forward sensing camera (FSC)]: Error signal received from electric power steering (EPS) control module. For Mazda6 and CX-5, the following error messages may appear in the instrument cluster. • Front camera sensor system malfunction • Forward Smart City Brake Support Malfunction • Driver attention alert system malfunction. This may be caused by the battery voltage falling and the EPS control module failing the initial learning for the steering center position while cranking. The FSC detects the error notified by the EPS control module. To correct this concern, the control software of the EPS control module has been modified while the repair procedure modifies the FSC for earlier repairs in the market.
MT-008-18	2018-10-09. Service bulletin. Some customers may complain about: Intermittent engine no start, Instrument cluster red security indicator light ON, Engine Start/Start Button Amber indicator, light flashing, Battery discharge, Electrical relay buzzing noise.This may be caused by: A key in a purse near a cell phone. The cell phone radio waves may interrupt the immobilizer system. An aftermarket cell phone charger. The charger may produce electrical noise that interrupts the immobilizer system. An aftermarket GPS tracker. Some aftermarket devices that are wired to the vehicles?s wiring harness may create unusual electrical symptoms.
MT-004-18	2018-10-09. Service bulletin. If you encounter any type of electrical concern (e.g, dead battery, engine no start, DTC(s) stored...), interview the customer before proceeding with normal Workshop Manual diagnosis. Aftermarket devices may be the cause of the electrical concern. Ask the customer if any aftermarket devices have been installed. Below are a couple of examples of unusual electrical concerns caused by aftermarket devices.
01-009-18-3452	2018-04-23. Service bulletin. The Mazda GR8-1291 is required for all warranty battery testing. If the Mazda GR8-1291 is not used, incorrect battery testing may result in unnecessary battery replacement. Use the following test procedures in this Service Bulletin to test Mazda vehicle batteries and to generate a Warranty Code.
01-008-18-3451	2018-04-23. Service bulletin. This service bulletin provides testing and charging procedures in order to promote proper battery maintenance, to deliver new vehicles with fully charged batteries, and to reduce unnecessary battery replacement cost. For new vehicles in stock at the dealer, inspect and maintain the battery periodically according to the repair procedure.