Understanding Toyota P320 Code: Oxygen Sensor Heater Circuit Issue

P320 is a fault code that can be found on some Toyota vehicles. It indicates a problem with the oxygen sensor heater circuit, which is responsible for heating the oxygen sensor in order to ensure accurate readings of the air/fuel mixture. Causes of the P320 code can include a faulty oxygen sensor, a damaged or disconnected oxygen sensor heater circuit, or a problem with the engine control module (ECM).