C003A: owner reports and bulletins

Chassis. We haven't written the explanation for this code yet. Below is what owners and manufacturers have filed with NHTSA.

Got C003A on your scanner? Tell the mechanic your year, make, model and any symptoms and you'll get the likely cause and what to check first. Ask about this code.

What owners report to NHTSA

6 complaints filed with NHTSA mention C003A, 5 of them since 2015, across 5 different models. The component owners most often filed it under: service brakes.

Manufacturer service bulletins that name C003A

30 technical service bulletins and manufacturer communications filed with NHTSA mention C003A, from 5 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • RAM 3500 (2019, 2020, 2021, 2022), bulletin 11011716: "Brake Warning Lamp Illumination Over Rumble Strips Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following Diagnosti…
  • JEEP WRANGLER (2020, 2021), bulletin 10183000: SENSOR, Wheel Speed Please call FCA Redacted Content prior to replacing a rear wheel speed sensor for one of the following fault codes: C003A-1D and or 2F (right rear wss circuit current out of range or signal erratic) C…
  • FORD EXPLORER (2020, 2021), bulletin 10186400: Some 2020-2021 Explorer/Aviator/Police Interceptor Utility vehicles may exhibit an illuminated anti-lock brake system (ABS) warning lamp with diagnostic trouble codes (DTCs) C0031, C0034, C0037, and/or C003A. This may be…
  • LINCOLN AVIATOR (2020, 2021), bulletin 10186400: Some 2020-2021 Explorer/Aviator/Police Interceptor Utility vehicles may exhibit an illuminated anti-lock brake system (ABS) warning lamp with diagnostic trouble codes (DTCs) C0031, C0034, C0037, and/or C003A. This may be…
  • FORD RANGER (2021), bulletin 10191090: Some 2021 Ranger vehicles built on 15-Jan-2021 and through 26-Feb-2021 may experience an illuminated traction control fault indicator in the instrument cluster (IC) with diagnostic trouble codes (DTC) C0037 and/or C003A …
  • FORD BRONCO (2021), bulletin 10204036: Some 2021 Ranger and Bronco vehicles built on 15-Jun-2021 and through 15-Aug-2021 may exhibit an illuminated anti-lock brake system (ABS) warning indicator lamp with diagnostic trouble codes (DTC) C003A, C0036, C0037, an…

Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.