hmmm..just hang out in this forum...i just drive Malaysia car... door lock for E90 become normal problem after 2years...if u just change the fuse,this prob will come back after few weeks... conclusion,change the door lock mechanism...why d fuse kaput after change new one?owhh,it bcoz d door lock consume alot of current,so the fuse blow it self to prevent door lock kaput..in this case,door lock already have internal electrical problem... if ur car just finish the warrty,then u treat ur service advisor as a frens..so they can help u in good ways....
im interested with topic key frequency....for merc and bmw,they more use radio signal... then it use "computer code" like 10001,........99999...every time u press the key,this code will change... dat y if some body want kipnap ur car,they must get the key.... w/o key they cant start ur car...if ur key missing or stolen,make the police report and bring ur car to SC.SC will block the key tread and the key missing can't use anymore...
for japan market,they use low frequency bcoz it govt policy...so the frequency coverage just around 3-5feets...