What is p0161 Chevy express 1500?

The P0161 code for a Chevy Express 1500 indicates a problem with the oxygen sensor circuit in Bank 2, specifically the heater circuit. This can signal that the oxygen sensor is not heating up properly, which may lead to poor fuel efficiency and increased emissions. Common causes include a faulty oxygen sensor, wiring issues, or a blown fuse. It's important to diagnose and repair the issue to ensure optimal engine performance.