U2105: owner reports and bulletins

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

Got U2105 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

8 complaints filed with NHTSA mention U2105, 1 of them since 2015, across 4 different models. The component owners most often filed it under: electrical system.

Most-reported models

VehicleComplaintsModel years reported
CHEVROLET COBALT52005, 2006, 2008

Manufacturer service bulletins that name U2105

5 technical service bulletins and manufacturer communications filed with NHTSA mention U2105, from 2 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • ISUZU N-SERIES (2022), bulletin 10214883: Dealers, upfitters or bodybuilders may notice various warning lights on the dash illuminating and certain DTCs without an apparent cause during the initial installation and connection of telematics, GPS, and/or other aft…
  • CADILLAC ATS (2013, 2014, 2015, 2008), bulletin 10114539: This Preliminary Information communication provides information to the technician about vehicles with the Service Engine Soon light is on, Reduced engine power message, no crank, multiple warning lights on, transmission …

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.