The battery is disconnected and reconnected for Renault vehicle. When the radio is protected by a four digit code. If you don't remember radio code, you need this App for calculator radio code via pre-code security. Input Code Guide: 1. With a Steering Wheel Remote Control: Press the [ ¬] button then rotate the thumb wheel for 1st digit Press the [ ¬] button then rotate the thumb wheel for 2nd digit Press the [ ¬] button then rotate the thumb wheel for 3rd digit Press the [ ¬] button then rot