U0300
0 owner reports and 33 manufacturer filings across 10 model years from Jeep, Mazda, Nissan.
Where U0300 shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2020 Mazda CX-30 | Electrical System | 5 | — | Battery → |
| 2020 Mazda Mazda3 | Electrical System | 5 | — | Battery → |
| 2019 Mazda Mazda3 | Electrical System | 5 | — | Battery → |
| 2021 Jeep Grand Cherokee | Electrical System | 4 | — | Battery → |
| 2021 Mazda CX-30 | Electrical System | 4 | — | Battery → |
| 2021 Mazda Mazda3 | Electrical System | 4 | — | Battery → |
| 2022 Mazda MX-30 | Electrical System | 3 | — | Battery → |
| 2023 Nissan Rogue | Power Train | 1 | — | |
| 2022 Nissan Rogue | Power Train | 1 | — | |
| 2021 Nissan Rogue | Power Train | 1 | — |
A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
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U0300 by make
The same record, one make at a time: the model years, bulletins and owner reports that name U0300 on that maker’s vehicles.
What it gets filed under
33 manufacturer filings name U0300. Start with what the maker wrote down.
A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names U0300.
- NTB23-085 Service bulletin2023-12-13 · Power Train
- ESM DIAGNOSTIC PROCEDURE UPDATE FOR DTC U0300 STORED IN TCM SERVICE INFORMATION The Electronic Service Manual (ESM) Diagnostic Procedure will be updated with additional information for diagnosing DTC U0300, for "CAN COMM DATA", if stored in the TCM. Refer to page 2 in this bulletin for updated Diagnostic Procedure. HINT: DTC can possibly be stored after TCM programming with CVT replacement
- SA-003-22d Service bulletin2022-03-11 · Electrical System — Software
- Mazda3 and CX-30: Prior to February 8, 2022, some vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction) and cannot be erased after a BCM replacement or MDARS BCM software update (NOT with BCM update for SSPC5 or 4621B using MDRT). This is caused by a BCM-VCM software error. MX-30: Some MX-30 vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction
- SA-003-22c Service bulletin2022-03-04 · Electrical System — Adas — Hud — Software
- Mazda3 and CX-30: Prior to February 8, 2022, some vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction) and cannot be erased after a BCM replacement or MDARS BCM software update (NOT with BCM update for SSPC5 or 4621B using MDRT). This is caused by a BCM-VCM software error. MX-30: Some MX-30 vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction
- SA-003-22b Service bulletin2022-02-09 · Electrical System
- CX-30. Mazda3: Prior to February 8, 2022, some vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction) and cannot be erased after a BCM replacement or MDARS BCM software update (NOT with BCM update for SSPC5 or 4621B using MDRT). This is caused by a BCM-VCM software error. Customers having this concern should have their vehicle repaired using the following repair procedure
- SA-003-22a Service bulletin2022-02-04 · Electrical System
- Some vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction) after a BCM replacement or MDARS BCM software update (NOT with BCM update for SSPC5 or 4621B using MDRT) and the DTC cannot be erased. This is caused by a BCM-VCM software error. Mazda is aware of the issue and is working on a resolution. If there is an issue with this concern, contact Hotline for newest repair i
- SA-003/22 Service bulletin2022-01-21 · Equipment
- Some vehicles may store DTC U0300:57 (Body control module (BCM) internal malfunction) after a BCM replacement or MDARS BCM software update (NOT with BCM update for SSPC5 or 4621B using MDRT) and the DTC cannot be erased. This is caused by a BCM-VCM software error. Mazda is aware of the issue and is working on a resolution. If there is an issue with this concern, Mazda recommends putting customer i
What U0300 means
Source: SAE J2012 / OBD-IIU0300 sits in the generic range of the OBD-II standard, so it means the same thing on every vehicle sold in the United States — but WhichTrim does not carry a definition for it and will not invent one. What is on this page is the record: who named it and on what.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about U0300
Source: NHTSA files and the OBD-II standardCan I keep driving with U0300 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.