Clearing Codes
WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 1991 Plymouth Colt Vista, 1991 Plymouth Colt, 1991 Mitsubishi Mirage, 1991 Mitsubishi Galant, and 1991 Mitsubishi Eclipse. However, it is still accessible from the selected car via links, so may be relevant.
Using DRB-II, from main menu select ADJUSTMENTS. Enter ERASE FAULTS. Follow DRB-II instructions to accomplish this task. If DRB-II is not available, fault codes may be cleared by disconnecting negative battery cable for at least 10 seconds, allowing ECU to clear fault codes.