Diagnostic trouble codes are the rudimentary language a car’s computer uses for communication. When the check-engine light in the instrument cluster of your 2003 Ford Taurus illuminates, it is letting you know the computer, known as a power train control module, has stored a diagnostic trouble code due to a malfunction in the engine management system. If the light is on, the diagnostic trouble code or codes must be read as the first step in troubleshooting the malfunction so it can be repaired and the light can be turned off.
Sitting in the driver seat of your Taurus, locate the diagnostic port under the driver-side dashboard and plug the datalink connector from your scan tool into the diagnostic port. The port will have a black plastic cap over it, marked with the letters “DTC” to identify it. The cap also serves to keep dirt and contaminants out of the connection port.
Follow your scan tool’s specific instructions located in the tool’s owner’s manual for performing a self test on the Taurus' power train control module. Depending on the particular brand and model of scan tool you have, this might be a very superficial scan that simply leads you to the codes, or it might be a more in-depth test. You will need to turn the ignition key to the run position during the test, but you will not need to start the car.
Read the codes on the scan tool's information screen.
Write the codes down on a piece of paper so you can refer to them when performing the troubleshooting. Each code corresponds to a specific pinpoint test that will help you diagnose the malfunction so your Taurus can be properly repaired.
Do not erase each code when prompted to do so unless you have diagnosed and repaired each malfunction. If you have done so, clear them; otherwise, select the "No" option when the scan tool prompts you to clear them.
