A friend took the battery out and told me to get it replaced. Now on enquiring from Halfords, apparently unless the battery is replaced with new one within 10 minuites, all the programme data is wiped off and key will need reprogramming. On looking at costs, it seems this could be £100 + via main dealer. Location: Sunderland tyne & wear. BigJohnD wrote a) Check the child locks on the rear doors. b) Check your "Settings" for what action is taken when using the key fob. There's a choice between "Driver's door only" and "All doors". On the child locks, I can't check them until I get the doors open. FAQ. FAQ #6. Change the C4 key fob battery? It's easy to do as the fob splits open easily inserting a small coin in the groove on the end opposite the actual metal key and twisting gently. They are simple watch 'coin' batteries and you may find them in a high street jewellers or clock repair shop and are. Coupe and Hatch: CR 1620 3v battery. The process is simple, when you have put the keys on the ignition of your Citroen C4 Picasso, in the event that the radio does not turn on automatically, all you have to do is press the power or "ON" button on the dashboard of your Citroen C4 Picasso. If the car radio is on the dashboard will light up then you will be able to set the radio Reset oil service light on Citroen c4 , with out computer. Using onboard computer system-~-~~-~~~-~~-~-Please watch: "Step-by-Step Guide: How to Replace Whee Yes, but it means a trip to the dealer as its done on their PC. if you search ebay for peugeot and citroen tyre pressure sensor valve stem kit you can replace just the valve stem bit for £20 and reuse the pressure sensor which is still coded to your car - a bit late if you've already chucked them. VSk7. Hi thanks for your responses everyone. I tried putting the key in the socket and starting to hopefully reset it but it didn't work. I took it in to the dealer this afternoon fully expecting to need a new door handle on the driver's side but they connected it to the diagnostics machine and reset it from there and now it's back working again.

citroen c4 grand picasso key reset