Is there anyway to know when the ecu has finished the relearn cycle, besides using a obd check, i goofed and waited to long to fix a check engine light and get emissions and now my tags expired so i can't really drive out on the roads, or to get to autozone and use an obd reader. my emissions all passed except for the "readiness" and i need to make sure before i go the ecu has fully reset, so i don't waste the money i already paid for emissions, doh! The dude at emissions said it usually takes 90-100 miles of driving, but I don't know if he knows what hes talking about. Thanks in advance!

 

You don't specify your MY, but this explains the newer ODBII drive cycle: http://www.obdii.com/drivecycleford.html

 

OP, it would help in answering your questions, if you would enter your truck info in your profile.

It takes several stop and goes, and the number I have heard is at least 50 miles.

 

Sorry about that, I have a 97 expedition 4x4 5.4l, thanks for the replies i did find more info on the drive cycle which answered my questions, now i'm wondering, i have a po401 code for egr flow and i read that 96-2001 model yr vehicles can have two not-ready systems in an emissions test and still pass, so i'm wondering if i was to get a scanner and clear that code would only one system show up as not ready? and would this allow me to then pass emissions? Which scanner tool is best that is capable of doing this that is readily available at the local auto parts store? I saw advance carries actron with these capabilities for like $180, is that a decent one for the price? Thanks again in advance.