Dhaval85

I have recently replaced the battery on my remote because the signal seemed to be getting very weak and this has sorted the range aspect out but my remote seems to be temperamental when trying to lock the car. Unlock works perfectly and straightaway but to lock the car sometimes the button works but most of the time i keep it pressed or even try a few times and it just will not work resulting in me having to lock car with the key.

It is a MY 03 and all advice welcome as not sure if need a new key & remote or issue with the circuit board in the remote.