U0420 on Mazda vehicles
U0420 is named on 10 Mazda model years (2017–2020): 19 manufacturer filings and 0 owner reports in NHTSA’s files, across CX-9, Mazda3, Mazda6, CX-5.
Which Mazda model years name U0420
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2020 Mazda CX-9 | Steering | 2 | — |
| 2020 Mazda Mazda6 | Visibility/Wiper | 2 | — |
| 2019 Mazda CX-9 | Electrical System | 2 | — |
| 2019 Mazda Mazda6 | Visibility/Wiper | 2 | — |
| 2018 Mazda CX-9 | Electrical System | 2 | — |
| 2018 Mazda Mazda3 | Visibility/Wiper | 2 | — |
| 2018 Mazda Mazda6 | Electrical System | 2 | — |
| 2017 Mazda Mazda3 | Service Brakes | 2 | — |
| 2017 Mazda Mazda6 | Service Brakes | 2 | — |
| 2020 Mazda CX-5 | Equipment Adaptive/Mobility | 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 U0420
Source: NHTSA manufacturer communicationsBulletins and campaigns Mazda filed with NHTSA whose summary names U0420. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 15-003-20-3737 Service bulletin2020-09-04 · Steering — Electric Power Assist System
- Some vehicles may exhibit that the SBS/SCBS warning light (amber) turns ON right after the engine is started with DTC U0420:68 [FSC] stored in memory. ï· DTC U0420:68 [Forward sensing camera (FSC)]: Error signal received from electric power steering (EPS) control module. For Mazda6 and CX-5, the following error messages may appear in the instrument cluster. ï· Front camera sensor system malfunc
- 15-003-20-3737a Service bulletin2020-10-02 · Steering
- Some vehicles may exhibit that the SBS/SCBS warning light (amber) turns ON right after the engine is started with DTC U0420:68 [FSC] (Error signal received from electric power steering (EPS) control module) stored in memory. For Mazda6 and CX-5, the following error messages may appear in the instrument cluster. ï· Front camera sensor system malfunction ï· Forward Smart City Brake Support Malfun
What U0420 means
Source: SAE J2012 / OBD-IIU0420 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. 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 U0420 a known problem on Mazda vehicles?
It is a documented one: NHTSA's files hold 19 manufacturer filings and 0 owner reports naming U0420 on 10 Mazda model years (2017–2020). 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 U0420 appear on most?
2020 CX-9 (2 documents), 2019 CX-9 (2 documents), 2018 CX-9 (2 documents).
Does U0420 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.