coding keyfobs from scratch...

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andyt109

Member
Posts
82
Location
Enfield/North London
can this be done?

1995 300tdi es,

standard imobiliser/alarm unit (single unit for central locking and alarm)

have a keyfob from the last unit which got wet but no keyfobs from new unit.

how can i code a couple of random single button fobs in?

both units are single button units.

thanks
 
Open the bonnet and ask the assistant to hold down the bonnet switch. Either get into the car and close the door, or wind down the window and stand outside.

NOTE: If you vehicle is fitted with a separate immobiliser, switch it off - as if you were going to drive the vehicle.

Instructions 1 to 7 must be done within 8 seconds!

1) Switch ignition ON
2) Switch ignition OFF
3) Lock doors - using sill button (press down)
4) Unlock doors - using sill button (pull up)
5) Release bonnet switch
6) Switch ignition ON
7) Switch ignition OFF

If the alarm is correctly accessed, the horn will sound and the red alarm LED will light and stay on. It is now possible to programme the key fob(s).

NOTE: A maximum of 2 key fobs can be programmed.

Carry out instructions 8 - 10 within 2 minutes.

icon_cool.gif
Press and HOLD down button on the first key fob until the alarm LED flashes a few times
9) repeat instruction 8 for the second key fob
10) The alarm LED will go out if both key fobs have been installed correctly

NOTE: If only one key fob is programmed, after instruction 8 turn the ignition ON and OFF to finalise the programming.
 
Open the bonnet and ask the assistant to hold down the bonnet switch. Either get into the car and close the door, or wind down the window and stand outside.

NOTE: If you vehicle is fitted with a separate immobiliser, switch it off - as if you were going to drive the vehicle.

Instructions 1 to 7 must be done within 8 seconds!

1) Switch ignition ON
2) Switch ignition OFF
3) Lock doors - using sill button (press down)
4) Unlock doors - using sill button (pull up)
5) Release bonnet switch
6) Switch ignition ON
7) Switch ignition OFF

If the alarm is correctly accessed, the horn will sound and the red alarm LED will light and stay on. It is now possible to programme the key fob(s).

NOTE: A maximum of 2 key fobs can be programmed.

Carry out instructions 8 - 10 within 2 minutes.

icon_cool.gif
Press and HOLD down button on the first key fob until the alarm LED flashes a few times
9) repeat instruction 8 for the second key fob
10) The alarm LED will go out if both key fobs have been installed correctly

NOTE: If only one key fob is programmed, after instruction 8 turn the ignition ON and OFF to finalise the programming.
will this work on a two button keyfob
 
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This only works if your replacement single button fob is working at the right frequency, there were about three different ones I think.
 
This only works if your replacement single button fob is working at the right frequency, there were about three different ones I think.

thats right , pay no attention to the bullshiit on ebay about the colour of the inside of the remote , that is incorrect , the only way to know for sure is to read the frequency off the alarm unit inside the passenger footwell , it faces away from you against the side of the car so a small mirror or dental mirror is handy to read it , shoulfd say 433.92 mhz or similar .
 
From VIN MA081992 all UK alarm units use 433 MHz before that it's 418 MHz.

Although the frequence is important it will remain the same, it's the communation data that is transmitted over that frequency which will change and which is held on the fobs EPROM and will have to be erased if you are using a second hand fob that is if the fobs EPROM is eraseable/rewriteable, it may have to be replaced.
 
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Its only the frequency that matters,secondhand single or two button fobs can be re-coded to different cars.Single button by the method described before,two button via Testbook or similar.If you end up using the Testbook method ask for the EKA code to be read at the same time - its the only surefire way to get it.If alarm ecu's get changed ,often LR traceability dont get told and the original EKA wont work.
 
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