Possible key fob problem?

[Dande]

Hey guys. Got a 07 2.2 d4d here. I went to unlock the car this morning about 7.30 and it wouldn't unlock. I had to manually use the key which set the alarm off. Got in and started the car and alarm still went off for another 10 seconds. 
It was the first frosty windscreen type morning here. Could the cold have caused a problem? 
It still isn't working now it's warmer though and I have changed the Battery. The old one looked a bit iffy and was about 2.9v. I have had to leave the car unlocked which is not great. 
Anyone had the same problem or similar? Would really appreciate any help. Tia

[Cyker]

I've had that occasionally in certain places with past cars, although not for many years now. (Now that I've said that I'm probably going to get jinxed now as my new car is keyless everything...!)

Speculation at the time was that nearby HAM radio operators or pirate radio stations or some other signal might be causing interference with the key signal, esp. as it was only in certain locations.

It could have been the key Battery if it's not been changed for a while; They supposedly need to be replaced every 2 years, but I've only replaced the Battery once in all the Toyotas I've owned so far! (The dealer is supposed to do it every major service but I know mine don't, even tho' they had the gall to list the Battery on the list of chargeable items!)

 

[arossco]

I've had my '06 2.2 D4D for eleven years and had this problem once not long after I got it.

It turned out that I had parked it next to a mobile phone mast, and came back about 4 hours later when it would not unlock. Same problem using the manual key and alarm going off. 

Glad to say it's never happened since !

[flash22]

Get the 12V Battery checked

[Dande]

On 11/3/2021 at 5:06 PM, Cyker said:

I've had that occasionally in certain places with past cars, although not for many years now. (Now that I've said that I'm probably going to get jinxed now as my new car is keyless everything...!)

Speculation at the time was that nearby HAM radio operators or pirate radio stations or some other signal might be causing interference with the key signal, esp. as it was only in certain locations.

It could have been the key battery if it's not been changed for a while; They supposedly need to be replaced every 2 years, but I've only replaced the battery once in all the Toyotas I've owned so far! (The dealer is supposed to do it every major service but I know mine don't, even tho' they had the gall to list the battery on the list of chargeable items!)

 

This is what I am thinking it is because it only happens outside where I live. I changed the Battery as well. It's literally every time I get home.

17 hours ago, arossco said:

I've had my '06 2.2 D4D for eleven years and had this problem once not long after I got it.

It turned out that I had parked it next to a mobile phone mast, and came back about 4 hours later when it would not unlock. Same problem using the manual key and alarm going off. 

Glad to say it's never happened since !

This is what I am thinking it is because it only happens outside where I live. I don't live in a majorly built up area though and I don't even know where the nearest phone mast or stuff like that is. It's really weird to be honest. 

17 hours ago, flash22 said:

Get the 12V battery checked

I have checked the Battery and it seems to be working well although thanks for the suggestion, I will keep an eye on it.

[Sooty]

You could try asking neighbours to turn their WiFi off while you test your key fob again.

Ask them 1 at a time as that will help to narrow down which one is causing the issue.

I had this once when staying at a hotel. Asked them to kill the WiFi for 5 mins while I tried the remote and all worked.

They turned WiFi back on and the remote failed.

[Cyker]

WiFi frequencies shouldn't affect the key remote signal, unless they're being amplified to illegally high levels (Can you get CB radio-style burners for a WiFi AP??  )

If you have a mate who does cabling work they might have a signal scanner they can use to see if there are any rogue frequencies spiking in the area, but that sort of thing is very specialist work and those scanners are expensive AF.

HAMs are usually easy to spot (Look for a 100ft antenna sat in their garden  ) and you just have to hope pirate radio stations get shut down by the authorities.

Off the top of my head other things that can cause enough interference if nearby are dodgy fluorescent tubes and those Networking plugs that use mains cables instead of proper ethernet cables.

 

[Dande]

Yeah thanks, It has to be something along these lines because it is only happening at home. I live in a little close type place with a carpark and whenever I park nearer to the houses it seems to do it. So I know what direction it seems to be. There is a tennis and bowls club so I don't know if they might have done something. I will keep a lookout for antennas lol

[FROSTYBALLS]

There are various things that operate on similar frequencies to and affect car key fobs - routers, wireless door bells, emergency services/armed forces transmissions, mobile phone masts, National Grid transmissions, etc.

[Cyker]

Yeah, I've even heard tell that it's a sign TV Licence vans or mobile speed camera vans are operating in the area!  (This is almost certainly untrue tho')

I know the immobilizer runs on a totally different licensed frequency and shouldn't be affected, but I think the keyless entry and remote central locking signals are on public frequencies which is why they are more likely to be affected (If anyone knows what frequencies exactly, that could help...!)