2003 Toyotas use a system known as on-board diagnostics, or OBDII, to ensure that the emissions equipment is functioning properly. The engine computer is constantly gathering data whenever the vehicle is running. If the computer senses one of the components of the emissions systems is malfunctioning, it will illuminate the check engine light in the dash. The check engine light must be turned off after the appropriate repair has been made.
Things You'll Need
- Adjustable wrench
Park the vehicle on a level surface and set the parking brake.
Disconnect the ground (black) cable from the negative battery terminal by loosening the retaining bolt and sliding the ground cable off the negative battery post.
Wait at least 10 minutes.
Reconnect the ground cable to the negative battery terminal.
Tips & Warnings
- If you have not repaired the system which caused the check engine light to illuminate, turning off the light will not fix the underlying cause. The light will illuminate again within a few hundred miles.
- Always remove the ground cable when disconnecting the battery. If you attempt to remove the positive cable first and the wrench or ratchet makes contact with the vehicle's body, electricity will arc through the wrench or ratchet and cause sparks.
- "Haynes Toyota Corolla 2003 thru 2005 Automotive Repair Manual"; Chilton; 2006
- Toyota Check Engine Light Answers
- Photo Credit Moody75/creativecommons.org
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