What is the meaning of OBD-II code P0135, and what are the possible causes and solutions for this code to be generated?

The code P0135 is a generic OBD-II code that indicates an issue with the bank 1 sensor 1 O2 sensor heater circuit. This problem was detected by the engine control module (ECM) during a test of the O2 sensor heater circuit. There are several possible causes for a P0135 code, such as: -Faulty Oxygen Sensor/Air Fuel Ratio Sensor -Malfunctioning Oxygen Sensor/Air Fuel Ratio Sensor Heating Circuit -Leak in the Exhaust System -Leak in the Intake Air System -Inadequate Fuel Pressure -Failed Engine Coolant Temperature Sensor -Issues with the sensor wiring and/or its electrical circuit -Requiring an update to the PCM software =Defective Powertrain Control Module. To diagnose the problem, a mechanic will visually check electrical connections, scan codes, monitor O2 sensor data, test O2 sensor voltage, check resistance, and follow the manufacturer's tests. The resolution to the P0135 code will vary based on the underlying cause. However, it often involves replacing the O2 sensor, fixing the wiring/connection, or replacing the fuse after correcting a short in the heater circuit. It's important to note that the O2 sensor heater helps warm up the sensor for faster feedback to the ECM. If the heater fails, the sensor may still provide feedback, but it will take longer than two minutes.