Typically the pads are good for at least a couple of thousand miles once the pad warning light comes on so there is time to get new parts sorted.

The light does not go on and off though so I suspect a fault.

There is a wire in the wear pad indicator which, once cut by the disc/rotor due to wear, breaks the electrical circuit and sets the dash warning light on permanently until such time as a new wear pad indicator is fitted.

I'd get the mechanic to check the pads again to be on the safe side.

Some people have got two sets of pads to one set of discs/rotors but normally the discs/rotors will need replacing along with the pads as the wear tolerance on the discs/rotors is very small before they are under size and out of service.

 

Exactly as Tommi said

 

You still have life in your pads..... it all depends on how long it took you to wear them out to this point, and then you can estimate how much longer that remaining 2mm will last you....

Brake linings
Thickness: 11 mm not including backplate.
Wear limit: 2 mm not including backplate.
When wear reaches a predetermined limit (approx. 4 mm) the warning lamp in the dash panel insert comes on.

 

Thank you all for the responses and advice. I had them checked by my mechanic who confirmed I still could use them for another 3-5 months and there is nothing to worry about the on and off alert.

 

Understand what I said.... your pads will still have life in them, but your sensors will get destroyed if you go beyond this point. I suspect that you are just at the point where you're starting to grind down one of the sensors, and this is why your warning goes away instead of being constant. You may want to pull your sensors out of the pads to save them if you want to get everything you can from your pads..... they can be pricey depending on where you get them.

 

I calculated remaining pad life at 25% of original. The remaining distance that you can drive is very much dependent on the conditions you drive in. In my case, I drove about 32,000km/ 20,000 miles once the light came on before changing pads, but I would suspect that I am an outlier on the high end.

SaVAGeSoot is correct about the brake wear indicators getting damaged if you make full use of your pads. I bought a complete set of Febi indicators for all four wheels from eBay for $37 USD.