Key fob battery change

[STEc74]

My sons battery on his key fob has gone flat and wont work locking,
can he change battery whithout losing code,also is there a time limmit to change.
His car is 2004 clk 230, any help would be appreciated.

Thanks Steve.

 

[television]

No codes to get lost, no time limit just withdraw the metal key, look in the slot on the side and you will see a grey/white block, press this towards the side with the tip of the metal key and at same time put you finger nail between the top and the case and the battery carrier slides out

 

[STEc74]

Key fob battery

Cheers for that will pass mesage on,will be pleased.

regards steve.