Q: PO153 02 circut low response bank2 sensor 1 What does this mean?

Your car has Oxygen sensors in the exhaust system to give the computer information on the fuel mixture. The Oxygen sensor produces a small voltage when it heats up and if there is oxygen present in the exhaust, as in a lean fuel mixture, the voltage drops sharply. The engine controller is constantly making small adjustments to the fuel mixture to keep the sensor voltage sweeping back and forth, usually about three times a second. If the oxygen sensor does not respond quickly enough to mixture adjustments, the controller will shift to a fixed mixture and store a code P0153 for the right bank sensor or a P014C for the left bank sensor. It could be a result of damage to the wiring, of an exhaust leak admitting excess air to the exhaust, or of a tired sensor. At 180 thousand miles it would not be unheard of for any of these things to be true. If you want to get this checked out at your convenience, you can contact YourMechanic. They will send a technician to your home or office to look at your Expedition and let you know what should be done for it.

Hi There. Thanks for contacting us tonight. The P0153 trouble code is an indication that the oxygen sensor is not properly regulating the fuel and oxygen levels. The oxygen sensor voltage switches between high voltage (fuel) and low voltage (air) at a rapid rate of speed. You might want to read this article to review the possible sources and solutions.