The Role of the Oxygen Sensor. ... This is unburnt oxygen that was initially injected into the fuel for proper combustion. Through a voltage signal, the O2 sensor communicates to the car's computer how much oxygen is in the exhaust, so that the computer can adjust the fuel/oxygen mixture delivered to the engine.
If the oxygen sensor is going bad, the fuel-delivery and fuel-combustion systems will be thrown off. If a bad oxygen sensor disrupts the air to fuel ratio mixture, or too much fuel is injected into the engine, your vehicle's gas mileage will be reduced.
5 Signs Your Oxygen Sensor Is Bad
Sudden decrease in fuel mileage. ...
Flashing check engine light or malfunction indicator lamp in the vehicle?s dash board. ...
Failure to pass smog. ...
Overall poor vehicle performance; rough idling, stalling, hesitation on acceleration, etc.
Vehicle engines that have a bad oxygen sensor often run irregularly or roughly.Oxygen sensors can control or contribute to many different engine functions, including fuel/air mixture, engine timing and engine combustion intervals. A faultyoxygen sensor can disrupt any of these things and cause a rough engine idle.
Bank 1 is where the Number 1 cylinder is located. This is always the forward most cylinder. So then if your diagnostic code is B1 S2 that means Bank 1 Sensor 2 down stream (post-cat). If its B2 S2 that means Bank 2 (opposite Bank to Bank 1) and thedownstream after cat o2 sensor.
While the oxygen sensor can indeed cause an engine to run poorly, slow acceleration could also be a clogged catalytic converter, or CAT. ... However, if theoxygen sensor goes bad, which may result in more emissions, the CAT can fail prematurely, so the two problems can actually run hand in hand.
If it fails it can cause automatic transmission problems such as late harsh shifts, early soft shifts, or can result in no shifting at all. The mass airflow sensor is directly related to engine performance, so an issue may affect the drivability of the vehicle and a poor running engine.