Clearing Trouble Codes
WARNING: This page is about a different car, the 1987 Toyota Supra. However, it is still accessible from the selected car via links, so may be relevant.
After any repairs are performed, clear ECU memory of all stored trouble codes. To clear memory, turn ignition off and remove the EFI fuse from fuse block for 30 seconds or more. The lower the ambient (outside) temperature, the longer the fuse must be left out. Replace fuse and exit diagnostic mode.