Technical
Service Bulletin

Mazda North American Operations
Irvine, CA 92618-2922

Subject:
BODY CONTROL MODULE (BCM) OR LOW FREQUENCY CONTROL
UNIT (LFU) REPLACEM

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

APPLICABLE MODEL(S)/VINS
2019 Mazda3 5-door HB (Japan built) vehicles with VINs lower than JM1BP******142784 (produced before
May 28, 2019)

DESCRIPTION
If the body control module (BCM) or the LF control unit (LFU) has been replaced and configuration has
been performed, communication between the BCM and the LFU may not work properly due to a difference
of the software level.
Symptoms:






If the BCM has been replaced:
Without a remote transmitter - the door lock switch at the liftgate will not lock doors
With a remote transmitter - the door lock switch at the liftgate will lock the doors even when the
front or rear door(s) are opened
If the LFU has been replaced:
 Without a remote transmitter - the door lock switch at the liftgate will lock the doors with the
answer back sound

Normal System Operation:

-

1. Door lock switch
pressed

LFU

-

BCM

3. BCM sends command to Door ESU for door
- 2. LFU sends command to - lock
BSM
- 4. BCM sends command to for rear side answer
back
Page 1 of 10

CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

REPAIR PROCEDURE
1. Verify customer concern.
2. Reprogram the ECU using the Mazda Diagnostic And Repair Software (MDARS). Refer to "MDARS ECU Reprogramming Procedure".




BCM replaced - perform LFU software update.
LFU replaced - perform BCM software update.

NOTE: Explain to the customer that the operation of the door lock switch at the liftgate has been modified
so as not to lock the doors when the key fob is not close to the liftgate.
3. Verify the repair.
MDARS ECU Reprogramming Procedure
ATTENTION: READ ALL CAUTIONS AND NOTES BEFORE AND AFTER REPROGRAMMING!
CAUTION:






A poor connection between the vehicle and M-MDS and/or low voltage may result in
abnormal termination and/or data corruption. A low battery voltage may cause a
reprogramming failure resulting in unexpected ECU replacement.
Make sure that the following connections are firmly connected, then DO NOT touch the VCM
and DLC cable to prevent noise and a poor connection.
 Between the vehicle-side connector and the DLC cable
 Between the PC-side connector and the USB port of the PC
When reprogramming with MDARS, power consumption and voltage fluctuation are greater
than with IDS. Use the Power Supply mode in the Battery Management System (GR8) and
connect an AC adapter to the PC to stabilize voltage fluctuation.

Page 2 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

BEFORE REPROGRAMMING
NOTE:








Turn off all electrical loads (i.e. A/C blower, audio system, rear defogger and headlights).
Perform a self-test and verify no DTCs are stored. If any DTCs are stored, repair the concern and
delete the DTCs.
Disconnect any aftermarket accessories (non-genuine Mazda accessories).
Terminate all programs other than MDARS on the PC. Running other programs may interfere with
the MDARS performance, resulting in the PC freezing or other problems.
Perform reprogramming with a proper internet connection. When using a wireless network, make
sure the connection is strong.
Make sure to keep enough free space on the PC’s hard disc. Insufficient free space (less than 1
GB) may result in the PC freezing during reprogramming.

1. Connect the M-MDS to the vehicle.
2. Launch the Mazda Diagnostic And Repair Software (MDARS).

Page 3 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

3. Turn the ignition on, then click “Start”.

4. Select the “toolbox” tab.

Page 4 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

5. Select Work Support group.

6. Select “Software update”, then click "Run".

Page 5 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

7. Select the ECU to be reprogrammed.

8. Confirm the current and new software versions, then click “Next”.
NOTE: When reprogramming the BCM, two softwares will be shown.

Page 6 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

9. Wait for the download, then click “Next”.
NOTE: When reprogramming the BCM, downloading will occur twice.

10. Read the screen instructions, then click “Next”.

Page 7 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

11. Follow the instructions on the screen, then click “Next”.

12. Wait for the reprogramming to complete.
NOTE:




The progress bar will stay at 90% for 30 seconds. This is not a failure.
When reprogramming the BCM, this process will occur twice.

Page 8 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

AFTER REPROGRAMMING
NOTE:



Select “Vehicle History” under “Collect Diagnostic Information”, then click “Run”.



Confirm the reprogramming on the screen and save the screen copy as a record.

Page 9 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.

Bulletin No.: 09-035/19

Last Issued: 09/27/2019

WARRANTY INFORMATION
NOTE:




If DTC B14F0:76 is stored and i-ACTIVSENSE warning light (Amber) turns on after BCM
replacement, refer to the 15-003/19.
If the BCM or LFU has been replaced for warranty repair, claim an additional 0.1 labor hours using
the labor operation number with “XRT” in place of the last three letters.

Example for MAZDA3 (BP) without 360°view monitor system

Without reprogramming With reprogramming
the other ECU
the other ECU
Replacing BCM T0108ERX / 0.3 Hrs. T0108XRT / 0.4 Hrs.
Replacing LFU
S1055BRX / 0.3 Hrs. S1055XRT / 0.4 Hrs.

Warranty repair

Page 10 of 10
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2019 Mazda North American Operations, U.S.A.