Hello All

My 97 Honda Odyssey won't pass smog because of an OBD system checks failure.
Why did this happen and how can I fix it?

Thanks

 

The Smog test said
"This Vehicle did not pass the OBD system check because the OBD system was not ready to test"
I did disconnect the battery but it was a long time ago ,since then i have driven quite a bit under varying conditions
So I wonder why I am having a problem now?
Help !
I don't have much time registration expires soon