[Mike SX]

Your clues are very good: interference at the home site. What has begun operating at the time the problem started? Neighbour's broadband? Ham radio operator? New phone tower?

Wireless Intruder Alarms etc can also trigger the problem 

[Lorian]

Zigbees, Video senders,wireless Alarms, weather stations, garage door openers, remote lights, external thermometers.

Typically it's going to be within 100 feet of the car.

[constipated]

Zigbees, Video senders,wireless Alarms, weather stations, garage door openers, remote lights, external thermometers.

Typically it's going to be within 100 feet of the car.

For me, there is nothing new in the house which should cause this. But can't vouch for 3 houses close by.

Just strange not to happen in 3 years and then bang, happening every few days.

[diablo]

I had this problem a week or so ago, when I pressed the unlock button on the key I got the lights flashing dimly but the doors didn't open. Tried spare key with same result. I then opened the door manually with the key, alarm went off but stopped a few seconds after I started the engine.

Obviously I checked this forum and this answer seemed the most likely -

When I had this problem on my 2009 model  i30 Estate it was due to the ignition switch not releasing the internal tumblers to enable remote locking. Always worse in hot weather. Puzzled me for ages until one day I noticed after I removed the ignition key there was a click inside the switch. Next time the remote didnt work I reinserted the ignition key and jiggled it to free the tumblers the Remote then worked. No click no remote. Improved reliability for a while by lubricating the switch very lightly with PTFE based light oil but Ignition Switch was subsequently replaced under warranty.

It hasn't happened to me since fortunately, though if it does I'll try WD40 or graphite on the ignition lock.  If it happens a lot I'll ask that they change it whilst I still have the guarantee.

It could possibly be interference, though I'd thought they improved this aspect of remote locking since my last car - which I could find unlocked when I returned to it - but only in a couple of locations.

[Phil №❶]

I had this problem a week or so ago, when I pressed the unlock button on the key I got the lights flashing dimly but the doors didn't open. Tried spare key with same result. I then opened the door manually with the key, alarm went off but stopped a few seconds after I started the engine.

Obviously I checked this forum and this answer seemed the most likely -

When I had this problem on my 2009 model  i30 Estate it was due to the ignition switch not releasing the internal tumblers to enable remote locking. Always worse in hot weather. Puzzled me for ages until one day I noticed after I removed the ignition key there was a click inside the switch. Next time the remote didnt work I reinserted the ignition key and jiggled it to free the tumblers the Remote then worked. No click no remote. Improved reliability for a while by lubricating the switch very lightly with PTFE based light oil but Ignition Switch was subsequently replaced under warranty.

It hasn't happened to me since fortunately, though if it does I'll try WD40 or graphite on the ignition lock.  If it happens a lot I'll ask that they change it whilst I still have the guarantee.

It could possibly be interference, though I'd thought they improved this aspect of remote locking since my last car - which I could find unlocked when I returned to it - but only in a couple of locations.

The proof for that would be that the key ALWAYS works in a different location, without fail. That would prove interference, not the keylock tumblers.

[eye30]

Anyone considered the mobile phone in your pocket may cause interference

[Berber]

Nothing to do with the location you are, when using the remote/s? Near a radio station transmitter or anything?

Sounds like it is related to the radio switch over, but could be just coincidence...

I had the same issue with my Civic. It turned out to be the location where I was parked. Moved it a few yeards away at either side and it was fine.

[The Gonz]

Yep. If we had the right bandwidth in the design of ours eyes and could visualise the crazy mess of electromagnetic radiation patterns, we'd easily see hot spots everywhere probably a few metres apart.

[TimH]

My 6 month old Crdi suffers the same intermitant non working key fob. Solved each time by opening any door and closing it again. Happens about once a month.