There is a bad ground cable.
It means that your relay is out, and has to be replaced with a new one, and once its been replaced, your check engine light will turn off in about 20 minutes or so.
One possible cause is a defective alternator, Have the charging system checked.
If the problem has been fixed and the light remains on you need to disconnect the battery and then reconnect it. That should reset the check engine light.
Disconnect the red terminal on battery and let it sit for 15-30 minutes, reconnect the battery and check engine light should be off because the computer has been reset.
it could mean that you have a loose battery cable that needs to be tightened
no no
you cant get it to work when it has been replaced.
i unhooked the battery...(both terminals)
Did you remember to clear the codes from the computer? OBD II systems have the ability to retain trouble codes even if the battery is disconnected so you will need a code scanner to retrieve the codes to have them cleared out so the computer knows the problem has been addressed.
Usally that means the battery has been disconnected within the last 10 starts
If you don't fix the problem that is causing the check engine light to come on you can unplug the battery a thousand times and the light will continue to come back on. Have the codes pulled and find out why it's turning it on in the first place.
There are pages and pages and items that can cause a check engine light. You need to have it checked for codes with a scan tool. After repair light can be shut off with scan tool.