2004 Subaru Impreza Owner's Manual - Page 113

Keys and doors 1 " Do not let dust, oil or water get on or in the transmitter when replacing the battery. " Be careful not to damage the printed circuit board in the transmitter when replacing the battery. ! Replacing lost transmitters HS2018BB 1) Positive (+) side facing up 4. Replace with a new battery (Type CR2032 or equivalent) making sure to install the new battery with the positive (+) side facing up. 5. Install the back half of the transmitter case. 6. Reinstall the two screws on the back of the transmitter case. After the battery is replaced, the transmitter must be synchronized with the keyless entry system's control unit. Press either the "LOCK/ARM" or "UNLOCK/DISARM" button six times to synchronize the unit. If you lose a transmitter or want to purchase additional transmitters (up to four can be programmed), you should re-program all of your transmitters for security reasons. It is recommended that you have your dealer program all of your transmitters into your system. ! Programming the transmitters The keyless entry system is equipped with a special code learning feature that allows you to program new transmitter codes into the system or to delete old ones. The system can learn up to four unique transmitter codes. The four transmitter codes may be the same or different. 2-10