Hi

 

A colleague of mine just came to me with a strange problem.

Unlocking with the remote does not seem to work. Also, if trying too many times the alarm goes off.

 

This is what I have found out:

1. The remote battery seems to be OK. The LED blinks when the unlock/lock buttons are pressed. Also, since the alarm goes off - something is actually transmitted between the car and the remote.

2. The physical key does not work to open the doors. It is pretty clear that the previous owner had the ignition lock changed. Also, this is the only key/remote she has.

 

So...

At this point the car is parked outside work and can not be opened. Does anyone have any idea what might have happened?

I was thinking maybe disconnecting the car battery and connecting it again might help, but that is easier said than done since I can not open the hood.

 

I tried googling around a bit, but did not find anything of interest.

 

If anyone has any information about this, I (and she) would be very thankful.

 

I have now opened the key. The label under the battery says 0678 433MHz. I decided to check whether the key is actually transmitting using a cheap RTL-SDR dongle and SDRSharp software.

 

There seems to be nothing wrong with the output, but the frequency is confusing me a bit since it seems to be closer to 444 MHz (~443.9) than 443 MHz.

 

I read somewhere that by sitting on your keys, keeping the buttons pressed for a longer time they could get "out of sync" with the car. I guess this has something to do with the rolling codes.

Is there a way of resetting this?

 

/Linus

Remotes use LPD433 (Low Power Device 433 MHz) which is a part of ITU region 1 ISM band that allows for licence free communication devices, using frequencies in the UHF band from 433.075 MHz to 434.775 MHz.

So at 433.887 MHz your remote is correctly operating within the band so should be recognised. Indeed this is probably why the door led blinks.

I assume that it is a factory fitted alarm and not an aftermarket unit with its' own fob.

You need the original door key to open the driver's door or boot. Then you need to switch on the ignition within 15 seconds to cancel the alarm.

I thought you may be able to break a window to switch off the alarm as above but this may not work if the immobiliser has not detected that the door has been opened first.

I believe the franchised dealers can obtain "work arounds" from VAG for situations like this. A search on the black side of the web may help!

Finally, try an automotive locksmith as they sometimes have deeper knowledge than you would expect. They are often used to provide new keys etc for cars that have been lifted by Baliffs and then auctioned.

I don't have a solution but my ramblings may help in your thoughts.

Any masts in the vicinity ... sigma ? they don't like interference...

Further thoughts: You need a key for the door. The only record of the lock number is held by Skoda, and they can supply a blade only key. Plus, you will need this key to be able to change the lock or to remove it in order to replace the remote locking unit if its failure is the root cause of the problem.

Not cheep but seems a sensible way out.