Fobs not working

[AndyFord]

Hey guys, so I have a Ford Focus ST Line 68 plate and I woke up this morning to the key fob not unlocking the car.  Pressing lock works fine but unlock or boot unlock doesn't work.  I tried the spare fob and had the same problem.  I used the key inside the fob to enter the car but it triggered the anti-theft alarm and the engine start button doesn't work.  I then changed the battery on one of the fobs with no luck.

Anybody else experienced similar issues or can diagnose what might be up?  A bit annoyed seeing as how I've only had the car for a few months.  My last Ford also went kaputz on me also because of faulty electronics.

[Ennvoqation]

A couple of things. First I'd check for corrosion on earth points. I've recently installed a dash cam, and had to clean some corrosion on connectors behind/beside the fuse box. Both of my key fobs was giving low battery warning up until that point and the dealer didn't have a scoobies what was going on despite replacing the battery.

The other thing to look at is there is a glitch with the zone locking system, I think you press door open/lock together for something like 4 seconds that will enable and disable the system.

 

 

[AndyFord]

So turns out the problem is that interference has caused the car to be unsynced with the keys.  It's a safety procedure built into Fords.  I guess to prevent key cloning?

So to disable the alarm, you have to get into the car using the key inside the fob, put the fob onto the key icon panel under the arm rest, which lets you start the engine and disables the anti-theft.   Then you have to go through a button press sequence/procedure to resync your car with the fobs.  This seems to solve the issue.  

[Ennvoqation]

Do you know what's the frequency of the fob for Ford, it'll be interesting to see what caused the issue. Thanks for the follow up.

[Comares2001]

To quote the handbook.

The radio frequency used by your remote control can also be used by other radio transmitters, for example amateur radios, medical equipment, wireless headphones, wireless remote controls, cell phones, battery chargers and alarm systems. If the frequencies are jammed, you will not be able to use your remote control. You can lock and unlock the doors with the key.

 

[Ennvoqation]

So probably somewhere in the 2.4Ghz range like Bluetooth/WiFi and microwaves. The latter being notorious for scrambling signals/electronics.

[Stoney871]

The keys work at 433MHz which is in the UHF band used by ham radio, taxi companies etc.
If you have any neighbours with a big antenna mast in the garden then they will cause you problems when they are on the air.
Some power socket plugs used in cars for USB charging and dashcams can also interfere with your RCL signal.
I used to have problems on an older car whereby my fob wouldn't remotely lock / unlock the car and found this stopped when the camera's power cable was unplugged.

Sent from my SM-G965F using Tapatalk

[AndyFord]

8 hours ago, Stoney871 said:

The keys work at 433MHz which is in the UHF band used by ham radio, taxi companies etc.
If you have any neighbours with a big antenna mast in the garden then they will cause you problems when they are on the air.
Some power socket plugs used in cars for USB charging and dashcams can also interfere with your RCL signal.
I used to have problems on an older car whereby my fob wouldn't remotely lock / unlock the car and found this stopped when the camera's power cable was unplugged.

Sent from my SM-G965F using Tapatalk
 

I don't have any antennas in my neighbourhood I don't believe.

I do have a dash cam that is constantly plugged into one USB socket (which powers off when car security lock triggers), and an AUKEY 12V-to-USB adaptor constantly plugged into the 12V socket.  Perhaps one of these caused the interference?  I have been using this setup for 3 months though.

One thing I know is that the 12V socket constantly supplies power hence why I don't plug the dash cam in.  And because I'm leaving the AUKEY 12V-to-USB adaptor in, perhaps it's supplying a constant current to the capacitors and coils, which in turn is generating some kind of interference? 

I'm going to leave these devices unplugged and see if the issue reoccurs.  It could be down to a deeper fault causing the unsync.

[Comares2001]

I've got similar items plugged into sockets and had no problems although actually the 12v sockets power down a while after car is locked.

[mrmetallica]

ive just got home from vets car unlocked going out went to lock it nothing ? any ideas ive changed the battery still the same

[TomsFocus]

5 minutes ago, mrmetallica said:

ive just got home from vets car unlocked going out went to lock it nothing ? any ideas ive changed the battery still the same

You might have accidentally pocket-pressed the button while it was away from the car which can unsync it from the car.  There is a procedure for re-syncing it but it was about 3 years ago I had to do it and can't remember now.  It might be in the handbook if you've got that handy.

[mrmetallica]

16 minutes ago, TomsFocus said:

You might have accidentally pocket-pressed the button while it was away from the car which can unsync it from the car.  There is a procedure for re-syncing it but it was about 3 years ago I had to do it and can't remember now.  It might be in the handbook if you've got that handy.

had the car 10 years and it never happened before i will look in the hand book cheers

[mrmetallica]

sorted thanks. who would have thought