Clearing Codes
WARNING: This page is about a different car, the 1992 Geo Prizm. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition switch to OFF position. Disconnect negative battery cable, or remove STOP fuse in fuse block, for at least 30 seconds. ECM fault code memory is now clear. If negative battery terminal is removed to clear ECM memory, clock and radio memory will also be erased.