Your 2003 Acura uses a second-generation onboard diagnostic module called the OBDII. The OBDII constantly monitors your Acura for issues with your engine, brakes and fuel delivery, among other things. When the OBDII identifies a problem with the Acura, the check engine light comes on to notify you that there is a problem. In the past, you had to take the vehicle to a repair facility to have the maintenance code checked. Now you can do it in the comfort of your own garage with an OBDII code reader and the code book that goes with it.
Plug the OBDII code reader into the OBDII port located under the dash panel on the driver's side of your Acura.
Turn the ignition key to the "auxiliary" position. This turns on the OBDII code reader and the vehicle's OBDII system.
Select "read trouble codes" on your OBDII reader. The reader displays a code that is specific to the issue that the system has identified.
Look up the code in your code book to determine the problem that the system has identified.
