This code indicates that the engine computer has detected an issue with the internal heater circuit of the oxygen sensor located on Bank 1, Sensor 3. The heater helps the sensor reach operating temperature quickly; a fault in this circuit prevents the sensor from reading exhaust gases efficiently during cold starts.
The internal heating element inside the oxygen sensor burns out or degrades over time, causing an open or short circuit.
Chafed, melted, or corroded wiring and connectors leading to the sensor can interrupt the power or ground to the heater circuit.
A dedicated fuse for the oxygen sensor heaters may have blown due to a short circuit, cutting power to the heating element.
A wiring fault in the ground path controlled by the engine computer can prevent the heater from activating.
The driver circuit inside the PCM that controls the heater ground has failed. This is extremely rare.
Generally, yes. Because Bank 1 Sensor 3 is downstream of the catalytic converter, it primarily monitors catalyst efficiency rather than fuel trim, so drivability is rarely affected. However, you will likely fail an emissions test.
In the vast majority of cases, yes. The heating element inside the sensor simply wears out. However, the wiring and fuses should be checked before replacing the sensor to avoid unnecessary repairs.
Usually not. Downstream sensors (Sensor 3) do not play a primary role in adjusting the air/fuel mixture, so a heater failure here rarely impacts fuel economy.
Almost never. Some mechanics may suggest a PCM failure, but the problem is the sensor or the wiring 99% of the time. The PCM should only be considered after all wiring, fuses, and the sensor itself have been definitively proven good.