OBD-II code · Fuel & Ignition
The downstream oxygen sensor is not getting its heater circuit commanded correctly. The internal heater element in the sensor is the most common failure — but a blown fuse, corroded connector or wiring fault mimics it exactly.
Replace the sensor and move on — usually the right call, but when it is a $3 fuse or a green connector, you have paid $300 for a repair you already owned.
Typical guess-and-swap cost: $250–$350 (sensor installed) when the fix was a fuse or pin cleaning
Check the heater fuse, measure sensor heater resistance against spec, and verify power and ground at the connector with the key on. Two minutes with a multimeter before any part gets ordered.
Mobile service in Canyon Lake, San Antonio & Austin. Written report with root cause — see a sample.