DTC 21: Code Word/Id Number Memorized In Immobilizer Unit EEPROM Cannot Be Read

Turn ignition switch to START position for 2 seconds. If SECURITY light flashes DTC 21 again, replace immobilizer unit and reprogram. See IMMOBILIZER UNIT  under REMOVAL & INSTALLATION. After repair, see IMMOBILIZER UNIT  under PROGRAMMING. If SECURITY light does not flash DTC 21 again, immobilizer system is okay.