C1201: owner reports and bulletins
Got C1201 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
10 complaints filed with NHTSA mention C1201, 6 of them since 2015, across 8 different models. The component owners most often filed it under: engine and engine cooling.
Most-reported models
| Vehicle | Complaints | Model years reported |
|---|---|---|
| TOYOTA TUNDRA | 3 | 2008, 2010, 2015 |
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.