1. Turn on the engine but don't start it. Put your key into the ignition and turn it to the "On" position (or "II" for some models), but don't crank the engine.
2. Quickly turn the key from "On" to "Off" three times. Be sure to do this within five seconds.
3. Leave the key in the "On" position. Do not start the vehicle.
4. The check engine light will flash the trouble codes. The light will blink a series of one-digit codes, followed by a two-digit code. The one-digit codes represent the tens digit of the two-digit code. For example, if you see the light blink three times, then pause, then blink once, that means the trouble code is 31.
5. Look up the trouble codes. You can find a list of trouble codes and their meanings online or in your vehicle's service manual.
6. Diagnose and repair the problem. Once you know the trouble codes, you can diagnose and repair the problem with your Cavalier.
