So I bought a fiesta mk7 pre face yesterday, and it has keyless entry and keyless, it worked perfectly fine yesterday and this morning but a few hours ago I tried to unlock it and it wouldn't, neither with the fob or the button on the handle, I unlocked it using the blade and holding the fob upto the steering collum where the ignition barrel would usually be allows me to start the car, but what could the problem be? it seems that taking the battery out of the key and putting it back in makes it work for about 5 mins but then it just stops working, and yes I've tried changing the battery.. 

Charge the car battery for 12 hours with a smart charger and it will be ok.

Search the forum for "State Of Charge"

14 minutes ago, unofix said:

Charge the car battery for 12 hours with a smart charger and it will be ok.

Search the forum for "State Of Charge"

I searched that and can't seem to find anything similar to the issue I'm having.. would the fob working after taking the battery out the fob and putting it back in still indicate the car battery needing charging or? since that's the case with mine.. 

The keyless entry needs the car battery to be in a good healthy condition.

Also keyfob batteries need to be of good quality (Poundland just don't work). Buy Duracell or Energizer from an electrical shop (not the local market). A new good battery should be 3.3 Volt

6 minutes ago, unofix said:

The keyless entry needs the car battery to be in a good healthy condition.

Also keyfob batteries need to be of good quality (Poundland just don't work). Buy Duracell or Energizer from an electrical shop (not the local market). A new good battery should be 3.3 Volt

the replacement key fob battery that I bought was duracell, and the previous was energizer, it may be the car battery needing charging like you said but firstly wouldn't that cause other things to stop working too or throw any other signs and secondly it'd still confuse me why taking the battery out the fob and putting it back in makes it work if the car battery was the issue 

The first 3 things that stop working when the car battery is low:

1- Stop/Start

2- Heated Front Screen

3- Keyless entry - first it disables passenger door and then if battery gets lower it then disables drives door.

Removing and refitting the battery in the keyfob, I can't offer an answer. Have you measured the voltage ?

3 hours ago, unofix said:

The first 3 things that stop working when the car battery is low:

1- Stop/Start

2- Heated Front Screen

3- Keyless entry - first it disables passenger door and then if battery gets lower it then disables drives door.

Removing and refitting the battery in the keyfob, I can't offer an answer. Have you measured the voltage ?

Voltage was fine, and the car doesn't have stop start (2009 model), and heated front screen worked.. However, I opened up the key and cleaned up the entire circuit board etc using cleaning alcahol and thankfully it's been working perfectly since(been about 5 hours), hoping it stays this way now, maybe it was just a bad connection due to dirt and opening and closing the fob made the connection more okay for a little while 

Pleased you have it working again.

It would be helpful if you completed your profile for the future so we can easily see what model and year you have.

22 minutes ago, unofix said:

Pleased you have it working again.

It would be helpful if you completed your profile for the future so we can easily see what model and year you have.

Ah yes, I'll do that now, I got the car like 2 days ago and forgot to update it and all posts before that were regarding me buying one,

Just incase anyone was wondering, I ended up getting the problem sorted by getting a new key.. I decided to get a new key made and reprogrammed since the key seemed like the issue and I only had one key anyway (always nice to have a spare), and ever since, with the 2nd key it's worked perfectly... I was told that the first key, which I was given with the car, had very obvious signs of water damage upon close inspection which would explain the temporary working