renault kangoo van central locking does not function any more it worked on monday key fob battery ok

Probably needs new battery

l think you should sell it to me but l will only take it if it 51 reg or newer white or silver in colour becouse this is fancyer and eh cheap as chip if none of this is you van well no deal

could be the engine management system. my mum had the same problem with her laguna - cost her £800

If the red warning light on the key no longer illuminates when u operate it, take the key apart & make sure the little switch has not come off the circuit board.
If it has it can be carefully soldered back on.
If the key has an optical eye by the key blade, check to see if the legs of the optical eye have not broken away from the circuit board, again these can be soldered back on.

The only other thing is the key may have gone out of syncronisation.
it maybe possible to resyncronise it by pressing & holding the central locking button down for a few seconds (with the ignition off) The door should lock & unlock, at this point operate the key about three times & hopefully it will start to work again. You may need to point the key towards the interior light as that is where the reciever is for the key signal on older kangoo's.

Otherwise it will need to go to a dealer.

Try cleaning the battery contacts inside your key a poor contact will cause your problem.