A friend of mine has a 08 reg Mondeo diesel with 6 gears, not sure of precise model but it has an alarm. Probably a Ghia.

A while ago her battery (ie the car battery) went flat and the immobiliser kicked in so she had to be brought home on a truck.

Now she's had a problem with the remote key - put a new battery in and still seems to be problematic. She tells me she can unlock the car with the key in the keyhole but she has to put the key in the ignition and start the car within a few seconds or the thing will do something disastrous - not sure if she means alarm or immobiliser.

I'm going to investigate this tomorrow when I see her and can look at her manual but I wondered if anyone was able to offer me some background info on this.

I can imagine that if the car's battery was flat the immobiliser might kick in but surely if the battery in the key runs out it shouldn't cause too much problem - you can still open the door by putting the key in the hole? What's this thing she says about having to start the car within a few seconds?

I think that the key and car need to be synced it's in the manual,

The keys just need re-syncing to the central locking system, a 2 minute job.

The 'disastrous' thing is the alarm sounding because the doors are being manually unlocked rather than via remote central locking (rcl).

It's a failsafe system whereby the car needs some verification that an authorised key is being used either by the rcl or the immobiliser (pats II) chip in the key when inserted into the ignition.

Once the keys are re-synced this will stop and remotely opening the doors again then this will be sorted.

Instructions for syncing keys is in the owners handbook (if you have one) if not give us a prompt and I'll post up the routine.

That's very encouraging, thanks, she has the manual so all should be well

How'd it go ?

I ended up setting my alarm off a few times when I was changing the battery. Basically you need to unlock the car via remote and leave a door open before you disconnect the battery. This disables the battery backup system, so when you replace the battery and play with the doors, the alarms dont go bonkers.

I must admit, after the countless times I swapped batteries earlier this year on my Mondeo, I never had to do any re-pairing!

hi

try this with master key turing key from off to acc fast 4 times

this should give a beep after beep do not take or move key from that position

and press unlock and lock on the key fob at same time while pinting it to the roof light near mirror then swiitch off ard remove master key it will be sorted mate

That's a bit of confusing Dave.

No such thing as a master key on these fords.

Doesn't matter who or what you point the key at, its a radio signal that's sent buy the remote.