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Alarm/Immobiliser problem on 172 Mark 1

Dear All

To cut a long story short,late last night my battery needed to be recharged by the AA has it wouldnt start after this was recharged everything was okay untill after i took it for a 20 min drive to recharge.

Has i was about to leave my girlfiends house i used my key plip opened the dorr and the alarm set off and never stopped for about 20 mins on and off and this was in a built up area at 23.00,not very nice.

Anyway the AA came again and the only thing to do was rip the Sigma alarm out and throw it in a bucket of water,the AA man also got the indicators to stop flashing.

The mark 1 Clio 172 didnt come with a alarm i seem to remember cuz i had the Sigma built into the car to work the the central locking and immobiliser.

Can someone tell me how the immobiliser works has i seem to think it doesnt now work but i have been told otherwise by someone in the know.

When i go to the car i press my key fob and the central locking unlocks,i then start the car and drive off,which is how it works........but if i do not press the key fob and unlock the door without the central locking and start the car i would have thought the engine shoudnt start,but it does.I dont know if this is right or not has i have been told it is okay.

The key fob activates your central locking and the engine immobiliser and once you put your key into the iginition the engine knows this is the right key so knocks the immobiliser off.

If got another key cut and used this to start the car it wouldnt start the engine because it has not got a transponder in it.

Does this sound right?

I have always had a few problems with my alarm i dont really like them preferring a decent immobiliser,but the sigma one i had was all built into the standard Renault key fob which i didnt like,it would have been better to have a seperate fob for it.If i get another alarm it wouild be a seperate unit on my key,can anyone help me with any suggestions on alarms,around the £150 price.

Thanks for your time


I am pretty sure that a UK purchased Mk1 came with an alarm - cos its Thatcham approved as is the immobiliser. If it was an import you would have needed (or where you bought it from would have needed) to get one fitted.

the transponder in the key switches off the immobiliser - I know this cos I had a problem with my immobiliser not switching off and it was because the transponder was damaged and I had to have a new key.

not sure how that helps, but that is as much info as I have !! :)

Thanks helps mate.

It was a import from Dublin,and thanks again for the info about the key,so the immobiliser is in the key.

Cheers mate.

Have you any suggestuions on decent alarms?



Ive got the Renault immobiliser and a Sigma after market alarm fitted.

The Renault Key has two codes associated with it (dont know why 2). The Renault key can go out of sync with the Renault immobiliser - essentially the engine will turn over but wont start because it cuts power to the coil I think.

If the Renault immobiliser doesnt recognise the code from the key the red light in the dash flashes continuously. Keys can be recsynced and in some cases need either a new battery or need to be replaced.

I can use my Renault key fob to lock the doors and enable/disable the engine immobiliser.

The Sigma alarm will also work lock the car doors and activate the alarm. Im not sure if it will activate the immobiliser. But that auto arms anyway after a period of time.

I have two different key fobs, one for Renault one for Sigma. The only problem I have had is with a Renault key not being recognised and thus new key on order. Car turned over but wouldnt start. This was a real pain in the neck.

Touch wood have had no problems with the Sigma.

Hi Simon

Yeah my ex alarm was Sigma,and my local alarm dealer fitted it but i didnt have a seperate key fob for the alarm,everything was done with the Renault key fob ie...central locking/alarm and immobiliser.I never liked having only key fob for everything my old Clio 16v had a screw near to the washer bay where you could turn the alarm off if it played up.

The only thing the AA could have done last night was take the alarm out and throw it in a bucket of water (which they did).

If i do get another alarm i will make sure that i get a seperate key fob for the alarm.

Is there anyway you can turn the alarm off on your 172 Simon if it plays up like mine did last night?