When replacing the battery on any cars with complex electronics and high end features the radio code, radio station memory, time clock ect.. are lost and have to be reset. Many cars require engine idle stratagy, seat memory, steering column, mirror memory ect... to be reset as well. When replacing the battery if possible it is advisable to use small jumper cables connecting a "live battery" to the battery cables when replacing the battery to ensure "keep alive memory" is not lost. Several after market companies sell a tool that plugs into the cigarette lighter but it requires the cigarette lighter to be live after ignition. The best tool I have seen is an Acura/Honda tool that plugs into the OBD2 socket under the dash but it is not advisable to just jump wires into this plug as serious damage will occur if the correct tool is mot used.