B1A03 on Mazda vehicles
B1A03 is named on 6 Mazda model years (2023–2025): 12 manufacturer filings and 0 owner reports in NHTSA’s files, across CX-90, CX-70, CX-30, Mazda3.
Which Mazda model years name B1A03
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2024 Mazda CX-90 | Seat Belts | 4 | — |
| 2025 Mazda CX-70 | Seat Belts | 3 | — |
| 2024 Mazda CX-30 | Seat Belts | 2 | — |
| 2025 Mazda CX-90 | Seat Belts | 1 | — |
| 2024 Mazda Mazda3 | Seat Belts | 1 | — |
| 2023 Mazda Mazda3 | Seat Belts | 1 | — |
A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.
Mazda filings that name B1A03
Source: NHTSA manufacturer communicationsBulletins and campaigns Mazda filed with NHTSA whose summary names B1A03. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 09-028-24 Service bulletin2024-05-21 · Electrical System
- Some customers may experience a warning message for the approaching vehicle audible system (AVAS) right after the ignition is turned on (POWER ON) while a loud noise, such as a horn, occurs close to the vehicle. Upon inspection, DTC B1A03:2B [ISB_AMP] (AVAS device circuit malfunction) is stored in memory. (AVAS Malfunction, Pedestrians May Not Hear This Vehicle Approach, Drive Safely, Have the Veh
- 09-028-24a Service bulletin2024-06-13 · Unknown Or Other
- Some customers may experience a warning message for the approaching vehicle audible system (AVAS) right after the ignition is turned on (POWER ON) while a loud noise, such as a horn, occurs close to the vehicle. Upon inspection, DTC B1A03:2B [ISB_AMP] (AVAS device circuit malfunction) is stored in memory. This may be caused by an internal initial diagnosis in the notification and warning amplifier
- 09-002-24b Service bulletin2024-06-22 · Seat Belts
- Some customers may complain that the warning sound in the passenger compartment (notifies i-ACTIVSENSE warnings, seat belt warning etc.) is too loud. Some of the volume settings in the notification and warning amplifier are not properly set. The control software of the notification and warning amplifier has been modified to eliminate this concern. CX-70 / CX-90 NOTE: This repair is also applicable
- 09-002-24c Service bulletin2024-07-08 · Seat Belts
- Some customers may complain that the warning sound in the passenger compartment (notifies i-ACTIVSENSE warnings, seat belt warning etc.) is too loud. Some of the volume settings in the notification and warning amplifier are not properly set. The control software of the notification and warning amplifier has been modified to eliminate this concern. CX-70 / CX-90 NOTE: This repair is also applicable
What B1A03 means
Source: SAE J2012 / OBD-IIB1A03 is a manufacturer-specific code: the second character is a 1, which under the OBD-II standard hands the definition to whoever built the vehicle. The same code can mean one thing on a Ford and something unrelated on a Hyundai. Any site that prints a single definition for it is guessing.
A stored code names the test that failed, never the part that caused it. The record above is what Mazda and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs B1A03 a known problem on Mazda vehicles?
It is a documented one: NHTSA's files hold 12 manufacturer filings and 0 owner reports naming B1A03 on 6 Mazda model years (2023–2025). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.
Which Mazda models does B1A03 appear on most?
2024 CX-90 (4 documents), 2025 CX-70 (3 documents), 2024 CX-30 (2 documents).
Does B1A03 on a Mazda mean it is recalled?
No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.