Q: Replaced both upstream and downstream o2 sensors. Should the engine light go off right away?

It is possible that the O2 sensors were never actually bad in the first place and that they were actually indicating that the catalytic converter is beginning to fail. I would recommend having your catalytic converter inspected by a qualified professional to determine if it is functioning properly. Many times when O2 sensor codes pop up on a vehicle the O2 sensors are replaced on this does not fix the problem. This is usually due to the fact that the O2 sensors were actually doing their job and indicating that the catalyst system is malfunctioning.

Hi Manuel. Thanks for contacting us tonight. Sometimes when an error code for an O2 sensor is triggered, it’s not caused by the sensor - but the electrical harness. Plus, anytime a code is set, it needs to be cleared by a professional mechanic once the repairs have been made. So, either the electrical harness is the fault or the code needs to be removed correctly.