P0191: 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 P0191 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

27 complaints filed with NHTSA mention P0191, 20 of them since 2015, across 19 different models. The component owners most often filed it under: fuel/propulsion system.

Most-reported models

VehicleComplaintsModel years reported
VOLKSWAGEN JETTA52009, 2010
FORD F-350 SD32021
CHEVROLET EQUINOX32013, 2017, 2023

Manufacturer service bulletins that name P0191

100 technical service bulletins and manufacturer communications filed with NHTSA mention P0191, from 13 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • RAM 3500 (2020), bulletin 10176587: Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module/Powertrain Control Module (ECM/PCM) with the latest available software. Customers may experience a Malfunction…
  • RAM 2500 (2020), bulletin 10180254: Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module/Powertrain Control Module (ECM/PCM) with the latest available software. Customers may experience a Malfunction…
  • ALFA ROMEO STELVIO (2019), bulletin 10170404: Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module (ECM), also known as a PCM with the latest available software. Customers may experience a Malfunction Indicato…
  • MACK GRANITE (GU) (2018, 2019), bulletin 10206134: Diagnostic Trouble Codes (DTC) P0069-64, P10EC-00, P0191-64 and P240F-00 In Different Combinations, Occurrences, And Time Stamps (Two To Four Codes), Possible Vehicle Derate - US17+OBD16, US17+OBD18 Emissions, Common Mod…
  • VOLVO XC60 (2018, 2019), bulletin 10206327: Diagnostic Trouble Codes (DTC) P0069-64, P10EC-00, P0191-64 and P240F-00 In Different Combinations, Occurrences, And Time Stamps (Two To Four Codes), Possible Vehicle Derate - US17+OBD16, US17+OBD18 Emissions, Common Mod…
  • ALFA ROMEO GIULIA (2017, 2018), bulletin 10170388: Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module (ECM), also known as a Powertrain Control Module (PCM) with the latest available software. Customers may exper…

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.