2002 Dodge Neon OBDII P1281 Code: Engine Cold for Too Long - Diagnosis and Fixes

I recently scanned my daughter's 2002 Dodge Neon and found OBDII diagnostic code P1281. The manufacturer-specific description states 'engine is cold for too long.' Based on this, I suspect either the engine thermostat or the engine temperature sensor could be at fault. I'm not sure if the vehicle is producing heat properly, so I'd like to know what other components or systems should be checked to confirm the issue. Any insights or troubleshooting steps would be greatly appreciated.