Daughters  keyless fob playing up. Problem started when she replaced the battery in the fob. Everything worked after battery replaced, doors locked/unlocked car started. Two weeks later car locked/unlocked but would not start the car. Started on emergence method.

Advised her to purchase energisers from shop and not ebay. Lasted more or less two weeks and again wouldn't start car. She purchased Duracell and put those in. Same thing again lasted two weeks.

Told her how to programme fob. Ignition from off to run 8 times, and leave in run position, within 10 seconds. Wait for doors to cycle lock/unlock and press any key on fob.

This she carried out but only got as far as the door locks cycle, lock/unlock, as nothing happened i.e. they didn't cycle lock/unlock.

Any ideas would be helpful before the dreaded new fobs and a visit to Ford and the expense that will incur.

Check the Voltage of the Batteries. It should be 3.3 Volts new and things will not work correctly when they get to 3.0 Volts.

If they are draining in two weeks then either they are faulty or the Fobs are not working correctly. 

In my car you get a message on the Dash to say that the Fob Battery is low.

I have had problems with big brand Batteries before so now I buy Supermarket own brand ones, no one is going to clone them and so far they are working ok.

Thanks for that John. I forgot to mention in my original post that she gets the message flash up "change battery". I am going to visit in a few weeks time and will take my volt meter with me and check the voltage of ones she has got and make sure a good one goes in.

Carrying on with this fob problem. Has anyone out there had experience of buying one of these used fobs of ebay. Also is there much work or problems matching it to the car or is it just the usual 8 on offs of the ignition switch?

If you are talking about a 2024 Puma, then it's Ford dealer job.

User programming of the PATS key was removed by Ford many years ago.

On 2/11/2025 at 4:37 PM, jsk said:

Thanks for that John. I forgot to mention in my original post that she gets the message flash up "change battery".

Just to be clear, is she STILL getting that message?

No Unofix. If you look at my original post it is my daughter's car which is a 2012 Fiesta. I should have mentioned that. Sorry

No Unofix. If you look at my original post it is my daughter's car which is a 2012 Fiesta. I should have mentioned that. Sorry

Yes she still gets the message "change battery". She changed the key battery and the message disappears for a fortnight of so. Then the process starts all over again.

At this point I should mention that the message refers to the key battery, NOT the car 12 volt battery which is good.

Poor quality battery

No good quality batteries with voltage of 3.308v on fitment. It appears to me that the fob is causing a drain on the battery. To date 4 good batteries fitted all flat within 2 to 3 weeks. That is why I am asking about the ebay fobs as a replacement before a visit to Ford.

20 hours ago, jsk said:

is my daughter's car which is a 2012 Fiesta.

OK 👍

Yes you can programme the keys on that model.

If you have two genuine original Ford keys then you can add a third using just the two keys that you have.

There are two parts to the programming of the keyfob. (1) The remote lock/unlock (2) The PATS immobiliser transponder.

If you don't have two genuine Ford keys then you will have to use FORScan (licensed version) to add new keys.