A P0135 code will appear on your scan tool when the bank 1, sensor 1 O2 sensor has failed. When the electronic engine control module (ECM) determines that the O2 sensor takes too much time to begin operating properly, the check engine light will appear, prompting you to use the scan tool and reveal the code. To keep the code from appearing and the check engine light from coming on, you need to replace the O2 sensor. The bank 1, sensor 1 O2 sensor is commonly referred to as the downstream sensor. Replace this sensor to ensure your vehicle passes a required inspection and continues to run efficiently.
Park the vehicle and allow it to cool for 10 minutes. This will ensure the O2 sensor is still warm but not too hot to the touch. This is ideal for easy replacement.
Open the hood of the vehicle and locate the bank 1 O2 sensor. The bank 1, sensor 1 is commonly referred to as the downstream sensor and is located directly before the catalytic converter with a wire running from the sensor to the Powertrain Control Module (PCM). The PCM looks like a small box-like electrical component.
Unplug the wire on top of the O2 sensor and set it aside for later use.
Loosen and remove the O2 sensor with a socket wrench and oxygen sensor socket. If you do not have access to an O2 sensor socket, you can use a 22 mm socket instead. Turn the socket counterclockwise to loosen and remove the sensor. Pull the sensor out of the vehicle and discard it.
Plug the replacement O2 sensor into place. Tighten and secure it with the socket wrench. Plug the wire into the top of the sensor. You will hear the wire click into place. Use the hand-held scanner to reset and erase the code per your scanner's instructions. The P0135 code should no longer appear. Close the hood of the vehicle.
