alhamy on 2000 Nissan Quest

am trying to clear the service engine soon out i cleared after i changed the first o2 senser am not sure should i change the second one or not

Asked by for the 2000 Nissan Quest
"Service Engine Soon" is unfortunate terminology used by Nissan. It doesn't mean the vehicle needs an oil change or maintenance, it signifies an emission system problem. This warning light is also called a Check Engine Light or MIL light, it requires a scan to turn off.
You said you replaced an Oxygen sensor. Which one did you replace and what was the previous trouble code stored?