The on-board computer in your 1997 Saturn monitors several input sensors that collect information concerning engine speed, load, driver input and fuel efficiency. The computer uses this information to calculate needs and drive output devices including injectors, timing advance/retard and transmission functions. If the computer detects a fault, it illuminates the check engine light and stores a code indicating the circuit involved in the fault. When the system is repaired, the warning light must be reset. However, unlike the older OBD systems that could be reset by disconnecting the battery, the 1997 Saturn uses OBD 2, and must be reset using a scan tool.
Attach the scan tool to the OBD2 connector located under the left (driver-side) of the dash, near the steering column. Take care when plugging the tool into the connector, as the pins are easily damaged.
Turn the engine on, and then turn the scan tool on. Select “Generic OBD2″ from the menu displayed on the tools screen. Select “Read Codes” on the next menu. Select “Current Codes” on the following menu. This will display all of the diagnostic trouble codes and their descriptions. It is a good idea to write down and keep those codes for future reference.
Select the “Back” function on the scan tool until you are at the menu that has “Clear Codes” or “Clear DTC” as an option. Select “Clear codes” or “Clear DTC”. The scan tool will display a warning message that the codes cannot be retrieved if erased, and will ask if you are sure you want to erase the codes. Select “Yes”, and wait for the message that the codes have been cleared. Turn off the ignition key, and then turn off and disconnect the scan tool. Test drive the car to verify the repair and check to see if the warning light comes back on.