[kutts]

Our Nissan Micra had both fobs not working - as in the batteries were flat. I changed the battery from a local watch repair shop for 50/-, it was the normal CR series coin battery you find in calculators. But, they simply would not work. I went to the Nissan service where they said that the normal batteries would not work and they use Sony make which provides the sufficient power. They were correct. It worked out to 400/- per battery so I just changed it in one fob. I need to see the price online to buy for the other one. I hope it works out cheaper online.

[Naveen_0181]

Originally Posted by arjab

So , if the remote keyfob fails, and one opens the door with the mechanical key, where will he or she insert the mechanical key to start the car?

If the key fob runs out of battery then it will work using the induced current. This is is the same principle how the wireless charging works on the mobile phone, we need to place the phone on the charging pad/base and the phone gets its charge by the induced current.

When you place the key fob physically on the start/stop button( or any other dedicated slot which varies with each manufacturer) the coil inside the fob gets close to the magnetic field generated by the start/stop button (same as what the wireless charger of the phone does) and it will induce a small current inside the fob( like the phone getting charged) and this small current is enough for the fob to generate the authentication code which will do the trick.

The key fob is required just for the authentication purpose and this authentication happens by transmitting a unique code which will be read by the car, this is similar to how the RFID cards works (Remember there wont be any battery inside a RFID card).


If the key fob failure is because of any other reason like physical/water damage, then this will be the same case as that of a broken/lost mechanical key, we need to have a replacement key or get the car towed to the service station!

[Ramon]

Originally Posted by Naveen_0181

When you place the key fob physically on the start/stop button( or any other dedicated slot which varies with each manufacturer) the coil inside the fob gets close to the magnetic field generated by the start/stop button (same as what the wireless charger of the phone does) and it will induce a small current inside the fob( like the phone getting charged) and this small current is enough for the fob to generate the authentication code which will do the trick.

I doubt that the start stop button has anything to do with transmission of unique code if any.

Atleast in my Ertiga Zxi+, the start stop button is just an electric button.

The reciever for the signal from the key fob is placed under the Center Console near the base of the hand brake and the second one is placed under the boot floor box at the base of the third row seat.

If at all the weak signal solution of holding the key close to the magnetic field is to work, the key should be held close to this sensor which is nearly impossible under normal circumstances as the sensor is inaccessible unless the Center Console or the boot floor box is dismantled.

[Naveen_0181]

Originally Posted by Ramon

I doubt that the start stop button has anything to do with transmission of unique code if any.

Hi Ramon, I am not saying the start/stop button will act as receiver/sensor, the position of the sensor can be at a different place, in my example the start/stop button will act as a wireless charger to provide some charge to the key fob when the fob is placed on/close to it, once the fob gets the charge the transmitted signal can be picked up by the sensor where ever it is in the car.

Placing the fob on the button( or other dedicated slot) is to give a temporary charge to the key fob.

I may not be 100% correct here, I would like to here from other experts in the forum.