How to reset immobiliser

Immobiliser is disarmed when the antenna around or near the steering lock receives the code held in the transponder chip within the key and then if that code matches the code in the black box memory it will send a signal to disarm the immobiliser.

It cannot be bypassed or otherwise disengaged except by a key with the correct code.

Undo the plastic casing around the ignition.
Its only around 4 screws easy.
look around the barrel where you insert the key, there should be a black plastic ring around 3 inches down the barrel this is the key reader its not fixed so twist gently and slide up the barrel as close to the key as the wires attached will allow.
then try starting, if it works then the transmitter in the key is most likely deteriorated . if it works its only a quick fix and could deteriorate in time.
a new key and coded from Renault is £300 with no guarantee that its not a different fault so look at buying one of ebay and get that paired to the immobiliser.
there is another way of bypassing the immobiliser by removing a ball bearing in the fuel pump a bit more complex.

does a security light flash on the dash if so the anti-theft has activated and will have to be reset, synced to the BCM if I remember I think you have to use the same colour key for things to work.

If it is not a new key fob, it sounds to me like the immobilizer is activated. So, all the lights on the dash are working now? Is there a flashing key on the dash lights? One of the resets that works is put the key fob in, and turn ignition on without starting it, and leave it 15 minutes. And try again.

the ignition relay may have gone. in the fuse box. or the immobiliser is not turning off. could be the chip in the key has moved. or the reader has failed. in key there is a black square should be sitting near to the key end. reader is fitted around the ignition barrel. immobiliser if the light is still flashing or flashes every minute it has failed.

Immobilisers may intercept one of three circuits; typically the low-voltage ignition circuit and the fuel pump circuit. Some may also intercept the low-current starter motor circuit from the key switch to the relay. The Immobilisers can be set to intercept these circuits IF you use a key that has been copied or someone tried to start the car with the key for another car. Once activated, most of the time they are on a timer, meaning they will reset in 10 to 20 minutes. You can try and reset yours by disconnecting the battery, remove both cables and touch the two cables together for ten minutes. Now if you have a radio that needs codes to reset it be sure you have the codes before disconnecting the battery. Some Immobilisers use a magnetic switch to turn off the car. buy disconnecting the battery and touching the cables together you will kill the magnetic field and reset it. Hope this helps fixya up.

Unfortunately the ignition barrel has been replaced with a new key,which has not been adapted to the immobiliser.The three core wire is from the reader coil which is supposed to fit around the ignition barrel.Obviously the key head was taped in the right position for the reader coil to read the key chip.Now the immobiliser is doing its job and cutting the ECU to stop it from running.It will take persiverance to find the right position to tape key back to coil for engine to run.Then your local VW Commercial dealership can readapt your key.

you can just try taking off the steering cowl and unscrewing the black cap (multifuntion switch/ignition switch) what about the steering lock?
If you have lost the keys forever then you may as well drill out the lock? youll have to buy a new ignition barell anyway.....
It's likely the car is immobilised though, it needs the proper key! although sometimes the immobiliser is disabled, sometimes it works sometimes it dosent...
good luck!
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most common cause is your key fob is broken.

check this by 1st gettin a camra phone goin onto the camra point key at camra and press button if you see a red light flash it is workin if not it is faulty which means a replacment key hope this helps

It could be the key aerial, located around the ignition barrel or a bad Immobilizer.
Try replacing the aerial, if you take the lower dash cover off (near pedals) you will find the immobilizer box bolted near the brake pedal. 
Remove this and look at the plug going into the box. You should have two blue wires with 12v at both with ignition on. Check to see if you have 12 Volts on both and just a faulty connection to the immobilizer. 
Three wires remain, two from the aerial around the ignition barrel and black which should be the ground wire.
Good luck and hope this helps. Oh and i believe you can not just turn off the immobilizer, sorry.