Just purchased a used 07 525 M sport Diesel tourer (my first bmw)
Every time I come to lock the car with the remote control, its a lucky
dip if it works. I have gone on a few long journeys to charge the fob and this seems to work for a short time but then dosnt work again.
Has anybody else had this problem or do I need to replace the fob.

 

Ya ive the very same prob as you maybe the battery is just f###ed

 

Do you have comfert access, if so check the key fob bateries. or look
Up diversity antenna issue.

 

I don't have comfort closing and the fob is a sealed unit.
The fob is supposed to recharge from the ignition.
What is this diversity antenna?

 

Your car is an 07 which means manufactured sometime in 06 probably so the rechargeable battery is ~5-6 years old. Do you have another key?

The antenna is what picks up the signal from the remote and usually shows itself as a problem with severe range degradation.

 

I do have another key and I have tried this with roughly the same symptons but thats as old as the other key.
I am reluctant to replace the fob as then it has to be matched to the car by BMW. Then were talking serious money.

 

I do have another key and I have tried this with roughly the same symptons but thats as old as the other key.
I am reluctant to replace the fob as then it has to be matched to the car by BMW. Then were talking serious money.

 

Both keys generally don't get the same usage (charged/discharged) so perhaps the problem is in the antenna. I agree on the price of the keys