Service Alert

Mazda North American Operations
Irvine, CA 92618-2922

Subject:
HEADLIGHT INOPERATIVE, WILL NOT SHIFT OUT OF PARK,
WARNING MESSAGES AND/OR DTC'S STORED

Service Alert No.: SA-023/21

Last Issued: 03/16/2021

BULLETIN NOTES
This Service Alert supersedes the previously issued Service Alert(s) listed below: The changes are noted in
Red.

Previous Service Alert(s) Date(s) Issued
SA-018/20

01/29/20

APPLICABLE MODEL(S)/VINS
2019-2021 Mazda3

DESCRIPTION
Some customers may complain about any of the following:

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Warning light
Warning message
Headlight(s) inoperative
Cannot shift out of Park
Many DTC's stored
Module communication errors

This may be caused by a damaged headlight assembly and/or water in the headlight assembly with any of
the possible DTCs:

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U300A:62-28:DSC - Ignition switch
B10A2:87-08:TCU - SAS control module collision judgement system malfunction
B10AD:09-08:BCM - Humidity sensor/solar radiation sensor/auto light sensor/rain sensor
malfunction
B10E7:16-08:BCM - IG1 relay circuit malfunction
P0615:13-08:BCM - Starter relay circuit malfunction
B1512:87-08:BCM - Communication error with indicator unit
U0155:00-08:BCM - Communication error with instrument cluster
U0164:00-08:BCM - Communication error with dash-electrical supply unit

Page 1 of 2
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.

© 2021 Mazda North American Operations, U.S.A.
03/17/2021 3:15 PM tlawrenc

Service Alert No.: SA-023/21

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Last Issued: 03/16/2021

U212A:00-0B:BCM - Communication error with light control module (LH)
U212D:00-08:BCM - Communication error with light control module (RH)
U212E:00-08:BCM - Communication error with door-electrical supply unit (driver’s side)
U213A:00-08:BCM - Communication error with door-electrical supply unit (passenger’s side)
U213B:00-08:BCM - Communication error with LF control unit
U213C:00-08:BCM U2131:00-08:BCM - Communication error with electrical supply unit (ESU)
U3004:16-08:BCM - ACC relay circuit malfunction
U2050:55-0B:BCM - Activation of remote control not implemented

REPAIR PROCEDURE
1. Verify customer concern.
NOTE: Check for collision damage and/or any signs of water in the headliamp assemblies. If water is found
inside the headlamp, check carefullyfor improper collision repairs. Collision damage and repairs are not
warrantable.
2. Disconnect one of the headlamp assembly electrical connector.
Do the DTC's clear?

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YES: Replace the headlamp assembly.
NO: Connect the headlamp assembly electrical connector, then go to next step.

3. Disconnect the other headlamp assembly electrical connector.
Do the DTC's clear?

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YES: Replace the headlamp assembly.
NO: Go to next step.

4. Disconnect the other headlamp assembly electrical connector (both sides disconnected).
Do the DTC's clear?

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YES: Replace both headlamp assemblies.
NO: Diagnose the vehicle using MGSS for the DTC's that have set.

5. Verify repair.

Page 2 of 2
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.

© 2021 Mazda North American Operations, U.S.A.
03/17/2021 3:15 PM tlawrenc