P0674: owner reports and bulletins

Powertrain (generic, all makes). We haven't written the explanation for this code yet. Below is what owners and manufacturers have filed with NHTSA.

Got P0674 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

1 complaints filed with NHTSA mention P0674, 1 of them since 2015, across 1 different models. The component owners most often filed it under: engine.

Manufacturer service bulletins that name P0674

3 technical service bulletins and manufacturer communications filed with NHTSA mention P0674, from 3 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • GMC SIERRA 1500 (2023, 2024), bulletin 10248263: This engineering information (EI) closure ends the need for gathering further information from technicians in regard to having the Check Engine Lamp illuminated on Driver Information Center (DIC) with DTCs P0671, P0672, …
  • CHEVROLET SILVERADO 1500 (2023, 2024), bulletin 10248263: This engineering information (EI) closure ends the need for gathering further information from technicians in regard to having the Check Engine Lamp illuminated on Driver Information Center (DIC) with DTCs P0671, P0672, …
  • RAM PROMASTER (2014, 2015), bulletin 10148966: Glow Plug Missing O-ring This bulletin involves the replacement of the glow plugs because of a missing internal O-ring. The customer may describe a Malfunction Indicator Lamp (MIL) illumination and/or a blinking glow plu…

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.