Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2021 Mazda 3 BaseFACTORY OEM SERVICE PROCEDURE

Telematics Communication Unit DTCS

TELEMATICS COMMUNICATION UNIT DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

DTC	Refer to
B10A2:09	(See DTC B10A2:09 [TELEMATICS COMMUNICATION UNIT] .)
B10A2:52	(See DTC B10A2:52 [TELEMATICS COMMUNICATION UNIT] .)
B10A2:87	(See DTC B10A2:87 [TELEMATICS COMMUNICATION UNIT] .)
B1142:12	(See DTC B1142:12 [TELEMATICS COMMUNICATION UNIT] .)
B1142:14	(See DTC B1142:14 [TELEMATICS COMMUNICATION UNIT] .)
B119F:01	(See DTC B119F:01 [TELEMATICS COMMUNICATION UNIT] .)
B119F:11	(See DTC B119F:11 [TELEMATICS COMMUNICATION UNIT] .)
B119F:13	(See DTC B119F:13 [TELEMATICS COMMUNICATION UNIT] .)
B1207:09	(See DTC B1207:09 [TELEMATICS COMMUNICATION UNIT] .)
B1207:23	(See DTC B1207:23 [TELEMATICS COMMUNICATION UNIT] .)
B1207:24	(See DTC B1207:24 [TELEMATICS COMMUNICATION UNIT] .)
B1207:86	(See DTC B1207:86 [TELEMATICS COMMUNICATION UNIT] .)
B1252:87	(See DTC B1252:87 [TELEMATICS COMMUNICATION UNIT] .)
B1A56:11	(See DTC B1A56:11 [TELEMATICS COMMUNICATION UNIT] .)
B1A56:13	(See DTC B1A56:13 [TELEMATICS COMMUNICATION UNIT] .)
B1D55:11	(See DTC B1D55:11 [TELEMATICS COMMUNICATION UNIT] .)
B1D55:13	(See DTC B1D55:13 [TELEMATICS COMMUNICATION UNIT] .)
U007A:00	(See DTC U007A:00 [TELEMATICS COMMUNICATION UNIT] .)
U0140:00	(See DTC U0140:00 [TELEMATICS COMMUNICATION UNIT] .)
U0151:00	(See DTC U0151:00 [TELEMATICS COMMUNICATION UNIT] .)
U0164:00	(See DTC U0164:00 [TELEMATICS COMMUNICATION UNIT] .)
U0415:86	(See DTC U0415:86 [TELEMATICS COMMUNICATION UNIT] .)
U0424:86	(See DTC U0424:86 [TELEMATICS COMMUNICATION UNIT] .)
U0452:86	(See DTC U0452:86 [TELEMATICS COMMUNICATION UNIT] .)
U2050:55	(See DTC U2050:55 [TELEMATICS COMMUNICATION UNIT] .)
U213C:00	(See DTC U213C:00 [TELEMATICS COMMUNICATION UNIT] .)
U2300:54	(See DTC U2300:54 [TELEMATICS COMMUNICATION UNIT] .)
U2300:55	(See DTC U2300:55 [TELEMATICS COMMUNICATION UNIT] .)
U2300:56	(See DTC U2300:56 [TELEMATICS COMMUNICATION UNIT] .)
U3000:00	(See DTC U3000:00 [TELEMATICS COMMUNICATION UNIT] .)
U3002:29	(See DTC U3002:29 [TELEMATICS COMMUNICATION UNIT] .)
U3002:56	(See DTC U3002:56 [TELEMATICS COMMUNICATION UNIT] .)
U3003:14	(See DTC U3003:14 [TELEMATICS COMMUNICATION UNIT] .)
U3003:16	(See DTC U3003:16 [TELEMATICS COMMUNICATION UNIT] .)
U3003:17	(See DTC U3003:17 [TELEMATICS COMMUNICATION UNIT] .)

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.

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