Car Wouldnt Lock

[lexus_IS_200]

yesterday pulled up at my house and the car would not lock via the central locking and also not when i tried via the key

so i tried starting the the car and it would start so i when and got my spare keys and it still wouldnt lock

so i moved the car onto the path and got out and it locked fine

what could this be?

[Chris.S]

do you live near any transmitters

[lexus_IS_200]

do you live near any transmitters

←

funny you shouls say that

i used to have a clio with a renault alarm fitted and i sold it to my g/f

and that is terrible for the car it would start in certain places on her drive due to the alarm and transmitters

never thought it could be that

[Rob]

can also be underground cables - best option, stand near drivers door /door pillar about 1 m away and try it then

[Mortimar]

This was happened to me once before .

The Wife hadn't fully shut the passenger door.

Shut fully car locked.

[Mr Pants!]

I had this outside a pub, the bloomin car would not unlock, so I used the key which set off the alarm, then my key thing worked, I went to Lexus to have the Battery looked at in the key and they said it was probably interference around the location I was parked.

[Niraj]

My old clifford alarm used to do the same thing, when i was near a phone transmitter aerial.

As for the lex, the only time it doesn't lock, is when another door is left slightly open, without realising.

[Damer]

Happened to me once parked next to a sub station. Also at the Trafford Centre.

[eXOBeX]

Apparently wireless LAN kit can also upset them.

[Kendo_Master]

Apparently wireless LAN kit can also upset them.

←

but why? wirless lan uses the 2.4GHz band while car key fobs use the 433MHz. I personally would say if its down to interference, the likely culprit would be the remote drive gates / garage doors as these use the 433MHz band too.

[The Editor]

Much more likely to be TETRA (TErrestrial Trunked RAdio) as used by the emergency services.

Do you have a hospital, police station, emergency service near you? - Emergency service transmissions are appalling in the way they limit harmonic distortions radiating from around the 400mhz region. Often just moving either you or the vehicle a few feet can alleviate the problem.

The other trick (and don't laugh at this one) is if you park your car, jump out and try to lock it and it just won't because of the above interference try holding the key fob to your head !! (I said don't laugh). Your skull will act as an antenna and should lock/unlock the car !! Don't believe me ???.... Try walking out of range of your key fob. Then try walking another 50 feet or so so that you KNOW you are definitely out of range. Now hold your key fob to your temple and push the button. Watch you indicators flash and your car unlock !! :D (I often use this method when walking back to my car across a car park. If I push the button and it doesn't unlock, I hold the fob to my head and viola... unlocked car !!

Oh and don't worry, the RF from a key trasmitter is much less that a mobile phone and at a lower frequency than microwave !

I now have visions of all LOC members walking about with their key fobs pushed to their heads !!

Enjoy...

The Ed.

[Kendo_Master]

Much more likely to be TETRA (TErrestrial Trunked RAdio) as used by the emergency services.

←

but again services that use the TETRA standard for their trunk radio dont use 433MHz, this is why one of many reasons the 433MHz was used. otherwise most cars in the uk will be having problems locking/unlocking doors and remember the radio signals from say ambulances will carries for many miles (obviously)

Emergency systems 380-383 MHz, 390-393 MHz (also 383-395 MHz and 393-395 MHz)

Civil systems 410-430 MHz, 870-876 MHz / 915-921 MHz, 450-470 MHz, 385-390 MHz / 395-399,9 MHz

Although some frequencies adopted from TETRA seem close to the 433MHz, it just does not meen you may get some interference on 433MHz applications. it does not make sense....

[The Editor]

Although some frequencies adopted from TETRA seem close to the 433MHz, it just does not meen you may get some interference on 433MHz applications.  it does not make sense....

←

It does if the equipment is badly designed/installed/maintained. The Harmonics that eminate from RF equipment can resonate up into the microwave regions. It's very concievable that spurious emmisions from TETRA causes malfunction in the 433mhz region. I'm not saying that it will constantly but RF is a VERY strange beast and NEVER conforms to computer models or expected patterns. (Mobile phone masts are a case in point - The coverage is never QUITE what the mobile service provider expects ! ) Although the primary frequency is always the strongest radiating from an RF transmitter there are always harmonics and sub harmonics of that frequency that will spew into the ether. It's these that cause the problem. I live fairly close (within 3/4 mile) to a hospital and have electric garage door openers on my garage. Over the past year or so I have noticed worsening range from my transmitters/recievers (and it wasn't me forgetting to replace the Battery :winky: ) In the end I decided enough was enough and ripped out the recievers in my door motors and replaced them with narrow band FM units. - Result?... I can now push the button on the remote before I even pull into my road and the doors will open :P . I've never had a problem since so I was definetely getting interference from somewhere.

Anyway... I need a lay down now after that reply...

Cheers

The Ed

[eXOBeX]

Apparently wireless LAN kit can also upset them.

←

but why? wirless lan uses the 2.4GHz band while car key fobs use the 433MHz. I personally would say if its down to interference, the likely culprit would be the remote drive gates / garage doors as these use the 433MHz band too.

←

It shouldn't, but it can.