U0122: 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 U0122 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

7 complaints filed with NHTSA mention U0122, 7 of them since 2015, across 7 different models. The component owners most often filed it under: electrical system.

Manufacturer service bulletins that name U0122

2 technical service bulletins and manufacturer communications filed with NHTSA mention U0122, from 1 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • SUBARU ASCENT (2019), bulletin 10155214: This bulletin announces availability of ECM reprogramming files to optimize the ECM. The new files contain logic which will revise: ? the ECM detection of DTC U0122 ? the EGR flow rate to address a limited number of cust…

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.