You have 2006 Hyundai sonata at 43000 miles. OBD diagnostic tells you ECM not ready after a battery exchange How do you get car ready for diagnostic test?

Answer 1

Usually when an OBDII vehicle comes up with codes for ECM not ready it's because the power to the ECM had been drained either from the capacitors or just general battery life was drained. With this being said if there is no power to your ECM or PCM your modules (computers) can't keep RAM on file. This RAM (or memory) are all the values and monitor tests that your vehicle does on it's own. So you will not be able to run diagnostic tests or pass plug and play emissions and safety tests for inspections. In order for your vehicle to see what it is going on it has to run it's own self monitors before it begin to do any diagnostic testing. These monitors usually are achieved in what is known as a drive cycle. It requires you to take the car on a series of timed accelerations, decelerations, idles and other load based engine driving parameters. you can usually find specific monitor requirement tables online. But you have to drive the vehicle in those specified ways in order for your car to complete it's monitors. After you've completed these monitors atleast the primary ones. you should be able to hook up to OBD and get some codes, tests ETC....