ok! you are right and this action is a good procedoure... but the contact key is knowless via ECU and this is the only engine start equip. that must be programmed
and first you must change the key batt,Then you must re-program the ECU.To do that,you only must insert the main key(with new batts installed) into the keyguard and turn to contact ON position wait a few seconds then Off,and so with the second programable key and,very important,the paperguard key too.This is because the three keys are an antenna system to close the electrical/electronic circuit via keyguard to ECU and restart the car... :luck: