I would check the 2" rubber hose because that is a VERY common problem on the villager. There is also a technical bulletin for the rear o2 sensor causing the cel. To be really sure you would need to scan the codes. The cel turns on if it detects the same fault twice,so your light will probably come back on if you clear it.
Driving cycle=van run with certain values established-eng temp/rpm/vehicle speed/etc..