P0167 - O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 3)

P0167 is stored when the Engine Control Module (ECM) detects a malfunction within the heater circuit of the oxygen (O2) sensor located downstream of the catalytic converter on Bank 2, Sensor 3. To provide accurate voltage signals quickly, the O2 sensor uses an internal heating element. The ECM monitors this circuit for specific resistance and current draw. If the heater's impedance is outside of the calibrated range or if there is an open/short circuit, the ECM will flag P0167. This prevents the vehicle from entering closed-loop fuel management efficiently.