Drive with caution — fix soon.
This code means the engine computer detected no activity from the upstream oxygen sensor on bank 2, so it's getting a flat or dead signal instead of the normal rich-lean switching. It's most often caused by a failed O2 sensor, but bad wiring, a blown fuse, or an exhaust leak can also trigger it. The usual fix is replacing the sensor, and it typically doesn't involve major engine repairs.
$150 – $400
Varies by vehicle and root cause.
Usually yes, for a short while. The engine will still run but may use more fuel and feel a little rough. Have it diagnosed within a week or two to protect your catalytic converter.
Expect roughly $150 to $400 in most cases. The oxygen sensor and labor make up most of the bill, though a simple wiring or fuse fix can cost less.
It's a moderate issue. It won't usually strand you, but the missing sensor signal forces the computer to guess, which raises emissions and can damage the catalytic converter if left too long.
It means the upstream sensor on bank 2 isn't switching the way a healthy sensor should. Instead of moving back and forth between rich and lean, it's giving a flat signal, which usually points to a dead sensor or a broken circuit.