Would you like to have your eyes opened to the truth about "so called On Board Diagnostics" Search internet for - Intro to On Board Diagnostics. The groups.engin.umd site will really shock you with the TRUTH about what you probably thought was your friend to keeping your car running. Oh-how wrong that propaganda is!
Find out the TRUTH ABOUT SO CALLED ON BOARD DIAGNOSTICS AND YOUR
MECHANICS FAVOURITE TOPIC - "I need to scan for codes"
I am NOT pooh-poohing mechanics here. I really think that most people, including mechanics, DO NOT KNOW WHY the sensors are there. It is a very informative explanation from a University ; ie: not from the manufacturers nor the government. It is the facts.