my 97 caravan, we ju7st replaced the engine with a good running exact same type and year 3.0 liter. it started right up but when I took it to WA state Emmissions station... it failed to get signals to or from catalyst, evaporative, heated O2, and EGR MONITORS? But it runs great- NO codes, but wont pass WA emmissions without these monitors working. someone told me that I just need to drive it for a few days to reset computer is that correct?
Thx, Rob :confused:

Try this link it is off the Washington State site.
http://www.emissiontestwa.com/e/OBDTutorial/004-OBD1.aspx

you need to drive it for a while, it needs to run through a drive cycle.