SERIOUSLY wierd car alarm / imobiliser / interference problem

[ProDave]

This one has got me stumped.

My Subaru Forester has a radio controlled alarm / imobiliser, factory fitted. The thing where you press a button on the key fob to unlock the car and disable the alarm.

So I'm back from 2 weeks away. Subara has been in my garage all that time.

I press the button, car unlocks. But it won't start. and after that initial unlocking, it will now neither lock nor unlock from the key fob.

Dead batteries? No. Neither main or spare key fob works and batteries checked and okay.

So after much huffing and puffing and thinking about expensive bills I find I can unlock and enable the imobiliser by typing the code into a keypad. (thank god the last owner left a sticker with the PIN and hadn't changed the pin)

So I drive up the road away from houses, and the key fob works. Drive back to my house, and it doesn't. I've driven up the street stopping outside every house in turn and it works everywhere except outside my own house.

So it's something in my house?

Nope. I turned off all the electric and still it won't work outside my house.

So it's something AT my house, not necessarilly in my house. If it is something in my house, it must be something battery powered.

So far I've tried removing the two radio controlled clocks, and tried removing the battery from my remote oil tank sender and it's not those.

Any ideas what it might be?

 

[SLIPSHOD & SLAPDASH]

No idea, but it happened to a load of us on a local job about 2 years ago. I had a Nissan van, others were 2 Transits and a Mazda amongst many.. There appeared to be a block on key fobs working. This was a cul-de-sac and i noticed a few neighbors using their keys in the car doors rather than zapping them

 

[Bacon]

I had a ford focus were the radio wouldn't pick any FM radio stations up after i went a way for 2 weeks,

That lasted for about 4 weeks then the FM radio stations came back on,

Then the following year it happened again bit this time they didn't come back on so i had to get another radio,

Strange but true.

 

[ProDave]

Mrs PD is home now. The key fob for her VW Touran still works. Must be on a different frequency?

Related to this. I have a Powermid remote control extender that uses the same 433MHz band as I believe the key fobs do. That is blocked too and not working. (but it's not the Powermids themself causing the problem as they are mains powered so would have been off when I turned the whole house off)

Next thing is to find some fresh batteries for my UHF amateur handheld transceiver and see if I can find the interfering signal on that. If I can it will make it easier to track down.

 

[SLIPSHOD & SLAPDASH]

We joked it must have been a Russian spy in the house nextdoor.

 

[steptoe]

:C

must be the time of year for weird stuff I guess.

 

[ProDave]

Okay getting close.

With my UHF handheld receiver I'm getting a very strong signal on 433.950MHz. the Key fob can be heard an the receiver on 433.925, so the interfering signal is on a very close, but not identical frequency.

The signal is strongest in the workshop above the garage, crammed full of electrical and electronic stuff.

The hunt is on now to find out what it is, bearing in mind it's not mains powered.

Almost like the X files.

Watch this space.

 

[OnOff]

Did a search for what transmits on 433.950MHz and one hit I got was a Wireless Weather Station.........have you / your neighbours got one?

(.....the only other hit was for a "Pink Jessica Rabbit Bedroom Bunny" whatever one of those is!)

 

[Evans Electric]

There was an area in Brum somewhere with the same problem, I think it was to do with a mobile phone mast .

 

[Evans Electric]

Thats a point Canoey, ....Dave is there a giant metallic circular craft hovering over your property?

 

[ProDave]

Still no luck.

Domestic duties and dinner gets in the way of such interesting investigations.

The problem I have, is once up in the workshop, the signal is very strong, registering full scale on the meter of the RX, and that's with the aerial unplugged and a dummy load in it's place. So trying to pinpoint the source is nigh on impossible.

I've checked the obvious, like may pair of 433 MHz walkie talkies. I've taken the batteries out and that made no difference. All mains power in the workshop is turned off. So it's got to be battery powered, but what?

Or there is indeed an alien space ship hovering right above us, above the clouds. hold on is that the men in white coats walking down the road.....

 

[OnOff]

There's not a spare fob somewhere with one of the buttons pressed down by something.............

 

[ProDave]

FOUND IT

Some time ago, more than a year ago I had a customer with a ceiling light / fan in their conservatory with remote control. The remote control receiver was not working. So I bought it home to try and fix.

I never did fix it, and found a replacement unit but the cost was too high so I converted it to manual operation.

I still had the remote control kicking around under a pile of "projects" on the bench.

And guess what, it's an RF remote control, not infra red, and yes, something had fallen on it holding one of it's buttons pressed.

Tell the X file team to stand down.

 

[Andy™]

must have a decent battery in it to last that long constantly transmitting

i sometimes get interference on my van remote at my unit - seems to be something to do with the hiab remotes on a neighbours daf

Another thing that could be an issure with interference is 433mhz is also used by some PMR radio's

 

[ProDave]

I don't think the button on the R/C has been pressed down for a whole year (otherwise I would have had this problem sooner) Probably less than a day. I went looking for something in the workshop this morning, and that's probably when the button got pressed down.

I wonder how long it would have been before the battery went flat had I not found it.

 

[SLIPSHOD & SLAPDASH]

Near enough all recent alarms have a anti-scan circuit which locks out the fob if another close frequency is seen. This will be most noticeable if you've left your motor in a car park and you have to press your own fob 2 or 3 times before your alarm will accept it.

 

[ProDave]

If I were a bit naughty, I could take this RF remote control and have some fun in a crowded car park.

But I won't as I'm a decent guy and have better things to do.

 

[Sharpend]

If I were a bit naughty, I could take this RF remote control and have some fun in a crowded car park.But I won't as I'm a decent guy and have better things to do.

Attach it too mrs pd's key ring!

 

[SLIPSHOD & SLAPDASH]

Kid hammers dads car in creative execution - YouTube

 

[bowly]

This one has got me stumped.

My Subaru Forester has a radio controlled alarm / imobiliser, factory fitted. The thing where you press a button on the key fob to unlock the car and disable the alarm.

So I'm back from 2 weeks away. Subara has been in my garage all that time.

I press the button, car unlocks. But it won't start. and after that initial unlocking, it will now neither lock nor unlock from the key fob.

Dead batteries? No. Neither main or spare key fob works and batteries checked and okay.

So after much huffing and puffing and thinking about expensive bills I find I can unlock and enable the imobiliser by typing the code into a keypad. (thank god the last owner left a sticker with the PIN and hadn't changed the pin)

So I drive up the road away from houses, and the key fob works. Drive back to my house, and it doesn't. I've driven up the street stopping outside every house in turn and it works everywhere except outside my own house.

Any ideas what it might be?

Hi Dave, An old thread that I came across via google. (I am not an electrician by the way)

I had the exact same problem last Friday with my 09 Subaru Legacy and  not having a clue rang my nearest dealer. They were busy so had to call me back. When they did, I was told that 2 other Subaru owners in my town (population 9000) had reported the same problem within an hour of me!  Following a 3 way conversation with the dealer and Subaru UK, the car was started using the keypad which I didn't even know existed before then. They suggested radio interference or power lines in the area could be the problem and try leaving it for a while. 

They were good enough to ring me back in the evening to tell me the other two cars were back to normal. Mine wasn't. The next morning I went out to the car and everything was back to normal.

We are not alone!!!