The 2012 Ford Focus has an oxygen sensor (o2) in the downstream of the evap framework. This implies that it tends to be situated after the exhaust system</br> while the upstream sensor can be tracked down before the converter. In the event that the sensor is defective</br> You will encounter side effects</br> for example</br> the check motor light coming on</br> an absence of gas effectiveness</br> a foul smell reMINIscent of spoiling eggs exuding from the fumes line</br> and delay of the motor while driving. On the off chance that the sensor should be supplanted</br> You can hope to pay between $12 a $45 for another one. On the off chance that You have it supplanted by a help proficient</br> You should pay an extra $50 to $180 for work.