My check engine light turns on when ever i drive my car for about 15 mins or so, then when i turn the car off and start it again it wont show up until 15 mins of driving. I tried doing the diagnostic test but it only showed up as "no data".Any one know's whats going on..?

 

first off obd1 or obd2 im guessing obd1 cause i shuts off when you turn the car off if thats the case check it with the car on!!

 

sorry its obd2b, and im running on a ctr ecu. so it cant be the secondary o2 cuz ctr's dont read the secondary o2. right or wrrong ??