Hi I am hoping someone could help me or point me in the right direction. I’ve got a 2011 Octavia 1.6 Diesel , original battery went faulty this week and I have just replaced it for a like for like, however the car only starts/ runs for about two seconds and immediately cuts out, it looks/ feels like the immobiliser is kicking in, whilst at the same time you can hear all the door motors clicking in and out, and they keep recycling every 15-20 seconds, numerous dash lights on as well . Tried spare Key fob, manually unlocking doors and disconnecting battery for 40 minutes all to no avail Thanks
 

Is there a procedure for re-synchronising  the key transponder back to vehicle, i.e. leaving it in the ignition for a period of time?

Your handbook is likely to have the procedure.

For my 2012 model it says:

 

Synchronising the remote control
If the vehicle cannot be unlocked by actuating the remote control system then it
is possible that the code in the key and the control unit in the vehicle are no longer
synchronised. This can occur when the buttons on the radio-operated key are
actuated a number of times outside of the operative range of the equipment or
the battery on the remote control was replaced.
This means it is necessary to synchronise the code as follows:
› press any button on the remote control key;
› pressing of the button means that the door will unlock with the key within 1 minute.

 

Try this then. Follow the procedure then lock the car with that key, then unlock again with the pushbutton.

Once the remote locking is working you will be able to start the car.

 

The other common procedure (not in the handbook) works only to clone to one key to a working key.

You can try putting key into ignition, turning to ON position, not starting car though, and press one of the buttons on fob for a few seconds, I don't know which button you press but this is usually the procedure for synchronisation.

 

To reprogram a key you'll need a scanner tool that suplies this function you'll also need software that has this function. You will also need a 4 digit PIN that you may need to get from the dealer.

I think that there may be some confusion going on here. If I am reading his post correctly, the OP has replaced his car battery with a like for like new battery and is having a problem starting his engine and is thinking that the keys and the immobiliser have gotten out of synch. This is not the same thing as the keys failing to unlock the doors remotely for which the other posters seem to be offering solutions.

 

As far as I know it is not normal for the transponders in the key fobs to go out of synch with the immobiliser when batteries are changed whether it is the batteries in the key fobs or the main car battery. Certainly I didn't have the immobiliser go out of synch when I replaced the main battery in my 2007 Octavia. I have a spare key that will not lock or unlock the doors remotely, but it will still unlock the driver's door manually and start the engine. My main key works correctly in every way. (I have tried various procedures to restore remote functionality to the spare key but without success, and the local dealer has also failed to fix it).

 

If there was a problem with the immobiliser, I would not expect the engine to start at all, rather than cutting out after a couple of seconds as reported by the OP, though I may be wrong about this. Therefore I am inclined to suspect that the OP's starting problem lies elsewhere. I have seen somewhere in these forums that some coding may be required on newer models when the main battery is replaced, but couldn't say whether or not this would apply to a 2011 car. Unfortunately cold damp weather conditions and being parked up during lockdown are not good for car batteries or the rest of the electrics. I hope these comments are helpful, although I don't know enough to be able to solve the OP's problem.

 

 

Can you measure the battery voltage, are you sure you've tightened the battery terminal nuts?

 

Other than that after a bit of research it could be your ECU gone bad, maybe some power surge to it caused a fault.

 

You could try a battery reset first.

On starting if it detects a wrong or no immobiliser chip in the key it will allow you to start the engine then it will stop up to 10 seconds later.

It will also bring up an immobiliser symbol on the display. 

 

Another possible cause is the sense coil or its wiring has failed. It is located around the key barrel in order to read the chip in the key.

 

 

Edited 5 February, 20215 yr by pikpilot

Hi. I had this issue or very similar and it turned out to be either the solder on the back of the speedo or a lose harness where it connects into the back of speedo but your issue does sound a little different. 
 

Edited 9 February, 20215 yr by Morph

If the cluster has a message NO KEY = Cluster cant see correct Key. So if you don't get that your key is ok

If your car starts and dies after a couple of seconds then that could mean an issue between the Cluster and ECU

 

best to get your car scanned with vcds to point you in the right direction