I've searched high and low but can't find any reference to this specific locking failure.

Following a change of car battery the car will only lock using the key blade. Both fobs are the same, after disconnecting and reconnecting the car battery the fobs will lock and unlock the car perfectly. After less than an hour the fob no longer locks the car. 

All help appreciated 

I don't know the answer but have you reset the Battery management system (BMS) after changing the battery?

Also, I believe if battery voltage is low or a failing battery very odd electrical issues can occur, is it a new batter, is it fully charged, maybe ask a garage/tyre shop to check the battery health?

and if you are able I would check for fault codes on the door locking/alarm system.

21 minutes ago, mattgs said:

have you reset the Battery management system (BMS) after changing the battery?

No BMS fitted on the 2009 Kuga Mk1

The battery you have fitted is not fully charged

1 hour ago, DaveT70 said:

The battery you have fitted is not fully charged

Thanks Dave, its a brand new battery reading 12.6 volts

3 hours ago, mattgs said:

I don't know the answer but have you reset the Battery management system (BMS) after changing the battery?

Also, I believe if battery voltage is low or a failing battery very odd electrical issues can occur, is it a new batter, is it fully charged, maybe ask a garage/tyre shop to check the battery health?

and if you are able I would check for fault codes on the door locking/alarm system.

Thanks Matt, as Unofix has said the car does not have BMS. 

The old battery was playing up ( hence why i changed it) but the replacement is fully charged.

Rather worryingly the obd2 port is not connecting to my diagnostic tablet, no voltage or anything present at the port so i'm a bit stumped. Maybe a fuse but i cant find any reference in the handbook to one.

2 hours ago, unofix said:

No BMS fitted on the 2009 Kuga Mk1

I find it quite unusual that the fob will lock to begin with and then stops after a short period. the unlock and tailgate buttons both work fine.

Is Kuga MK1 Focus MK2.5 or MK3  based, I can't remember

2 minutes ago, DaveT70 said:

Is Kuga MK1 Focus MK2.5 or MK3  based, I can't remember

I believe its based on the mk2

 

Yes, Mk2.5 Focus.  Released in 2008.

Instrument cluster or BCM issue then??

Update

The fob locking works fine until I enter the security code into the radio. As soon as I do that the fob locking stops working.

I know it sounds far fetched but that's where I've got too so far. I've not entered the radio code this time and intend to wait a day or so before I try it again. I'll keep you posted.

This sounds like the classic case of the modules have booted up out of sync when the new battery was fitted.

The usual fix that sorts all of these problems out is to do a full system restart.

Disconnect the negative battery lead and leave it disconnected for 20 minutes. Then reconnect the battery negative and WAIT a full 5 minutes before turning on the ignition. This will allow all modules to reboot and in the correct sequence.

30 minutes ago, unofix said:

This sounds like the classic case of the modules have booted up out of sync when the new battery was fitted.

The usual fix that sorts all of these problems out is to do a full system restart.

Disconnect the negative battery lead and leave it disconnected for 20 minutes. Then reconnect the battery negative and WAIT a full 5 minutes before turning on the ignition. This will allow all modules to reboot and in the correct sequence.

Thanks, I'll try this tomorrow.

19 hours ago, unofix said:

This sounds like the classic case of the modules have booted up out of sync when the new battery was fitted.

The usual fix that sorts all of these problems out is to do a full system restart.

Disconnect the negative battery lead and leave it disconnected for 20 minutes. Then reconnect the battery negative and WAIT a full 5 minutes before turning on the ignition. This will allow all modules to reboot and in the correct sequence.

I've tried this process twice now and I still have the same problem. If i can get to the bottom of why the obd2 port doesn't work maybe something will be revealed.

Probably a stupid suggestion but as a test if you still have the old battery can you charge it up and see if system works with that one?

9 hours ago, mattgs said:

Probably a stupid suggestion but as a test if you still have the old battery can you charge it up and see if system works with that one?

It drops to 10.5v 24hrs after a charge so definitely no chance of that working. The new battery is holding a steady 12.4v in situ. I will try another battery though, thanks for the suggestion.

Update

So following a suggestion from Unofix I disconnected the battery, then removed the fuse for the radio and reconnected the battery. Then the fob locking was working fine so i ran through the diagnostics and cleared all the faults that had appeared due to battery disconnection and fuse removal. Then I reconnected the battery and all is well.

Thanks so much for all the help.