The engine control unit (ECU) on a Ford Contour is a small on-board computer inside the engine compartment that's responsible for controlling all of the engine's electronic components. When it senses a problem, it stores a diagnostic trouble code (DTC) in its memory and turns on the service engine light on the dashboard. An automotive scan tool connected to the Contour's diagnostic data port is required to clear the trouble codes and reset the ECU.
Place the Contour's transmission in park (automatic transmission) or first gear (manual transmission). Engage the emergency brake and turn the ignition to the "Off" position. Rotate the ignition back to the "On" position but do not start the engine.
Plug the scan tool's data cable into the Contour's diagnostic data port, underneath the dashboard just above the pedal area. Turn on the scan tool and allow it to start up.
Follow the instructions on the scan tool's screen to enter engine and transmission information.
Choose "ECU" from the main menu. Select "Codes" and "Clear all current and stored DTCs." Wait for the scan tool to indicate that the codes have been cleared.
Unplug the tool's data cable from the diagnostic data port. Start the engine and ensure that the service engine light is not illuminated.
