Mazda bulletin SA-012-26d
What it saysDESCRIPTION Some customers may experience a message "TCU Malfunction. NHTSA’s full summary ↓
Mazda filed this with NHTSA as a service bulletin dated Sep 18, 2026, received Oct 1, 2026, about the electrical system. It names 17 model years (2024–2027). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationDESCRIPTION Some customers may experience a message "TCU Malfunction. Have the Vehicle Inspected" in the instrument cluster. Additional symptoms that may occur: Connected Vehicle One Time Passcode (OTP) may fail. Connected Vehicle Remote functions may fail. The following DTC's may be stored: B1252:87-8B:TCU - COMMUNICATION ERROR WITH CONNECTIVITY MASTER UNIT (CMU) U0198:00-03:CMU - COMMUNICATION ERROR WITH EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT REPAIR PROCEDURE 1. Verify the concern. 2. Check if any of the following DTCs are stored: B1252:87-8B:TCU - COMMUNICATION ERROR WITH CONNECTIVITY MASTER UNIT (CMU) U0198:00-03:CMU - COMMUNICATION ERROR WITH EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT Are the following DTCs stored? YES: Proceed to next step. NO: This service information does not apply. Continue troubleshooting using MGSS.
Trouble codes it names: B1252 U0198
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| SA-012-26d | Service bulletin | Sep 18, 2026 | 11037632 | PDF, 186 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themAlso filed against model years this site has no page for: 2027 Mazda CX-50; 2027 Mazda CX-50 Hybrid; 2027 Mazda CX-90; 2027 Mazda CX-90 Plug-IN Hybrid.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 13 model years this bulletin names have filed 689 complaints with NHTSA since 2015. 101 of them name Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
Instrument cluster will reboot during braking at random times. All warning lights turn on, gauges go to zero and front wipers are set off. This happens for 1-3 seconds. Mazda replaced instrument cluster but only made issue worsen they said it’s safe to drive but very distracting especially when turning onto busy roads.
2026 Mazda CX-90 · Electrical System · filed with NHTSA Jun 10, 2026
The vehicle has major electrical issues. The ABS and all over driver safety options would shut off for days at a time. I had purchased this cx30 as new on January 02, 2026. It totally died and wouldn't start on February 03, 2026. It had to ve towed by mazda roadside assistance to Towne Mazda dealer in Orchard Park NY.
2025 Mazda CX-30 · Electrical System · filed with NHTSA Mar 12, 2026
I was denied work on a network issue recall 3 separate times at the dealership I bought the car. The first time I was told it was because of a smell. If I clean the car, they will fix it. I noticed after they were in the car my backup camera didn’t work which I also thought might be a recall but found out it wasnt.
2024 Mazda Mazda3 · Electrical System · filed with NHTSA Aug 7, 2026
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the electrical system
Source: same model, same component group174 other manufacturer communications filed against these Mazda models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Mazda list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 09-027-26 | Service bulletin | Sep 29, 2026 | DESCRIPTION Some CX-70 and CX-90 PHEV vehicles may fail to start (enter READY mode) in cold weather, but the vehicle can often be started su… |
| SA-038-26b | Service bulletin | Sep 10, 2026 | This Service Alert supersedes the previously issued service alert listed below. The changes are noted in Red text. SA-038/26 08/18/26 and 06… |
| SSPE1 | Emissions | Aug 20, 2026 | Special Service Program (SSPE1) - 2026 CX-50 Hybrid – Battery Label Concern Mazda Motor Corporation has decided to conduct a Special Service… |
| SA-054-26 | Service bulletin | Aug 20, 2026 | This Service Alert supersedes the previously issued Service Alerts listed below: The changes are noted in Red. Infotainment Reboot With Nav… |
| SA-053-26 | Service bulletin | Aug 19, 2026 | This Service Alert supersedes the previously issued bulletin(s) listed below. The changes are noted in Red text. SA-006/23 01/23/23 DESCRI… |
| SA-039-26a | Service bulletin | Aug 19, 2026 | This Service Alert supersedes the previously issued SA(s) listed below. The changes are noted in Red text. SA-039/26 06/15/26 Mazda Connect… |
| 8026C | Emissions | Aug 19, 2026 | 2026 CX-50 Hybrid Battery Label Concern - Emissions Recall 8026C Mazda Motor Corporation has decided to conduct a Voluntary Emissions Recal… |
| SA-051-26 | Service bulletin | Aug 15, 2026 | This Service Alert supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-076/24 10/22/24 DESCRIPTION This Se… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mazda, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mazda SA-012-26d a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the SA-012-26d repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does SA-012-26d cover?
The manufacturer filed it against 17 model years: 2026 Mazda CX-30, 2025 Mazda CX-30, 2024 Mazda CX-30, 2026 Mazda CX-50, 2025 Mazda CX-50, 2026 Mazda CX-70 and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.