My nissan car key fob not working

Seeing the date that you posted this, I wonder if this has been resolved?

For your car, if the remote does not open the car door after the battery in the fob has been replaced, do this.
1. Get next to the car with doors locked
2. Push the Unlock button 4 times in succession as you count, one, two...
3. The remote receiver should recognize your fob now

As for the dash LED, it may be unplugged somewhere. The DI cassette has little to do with it. LEDs have an ginormous life span and should not go dead - at least for the life of your car. Does it EVER flash?

If the passkey is messed up, there will be a light on the dash that says security, or have a picture of a car with a lock thru it. If there is no light when the key is turned forward, then its NOT a passkey problem.

do you have the owners manual? Usually you have to turn the key back and forth a series of times. I know Ford has to be 10 times back and forth in less than 30 seconds. Then you aim the fob at the reciever on the dash. The owners manual should tell you. Ill give you a general nissan recode, im not sure if it will work for your Nissan.
. Place your key in the ignition and switch from the LOCK position to the ON position 6 times within 10 seconds ending with the key in the LOCK position
If done correctly the indicators should flash 2 times
2. Press and hold the UNLOCK button (black on P11) on your keyfob and while keeping it pressed then push the LOCK button (Red on P11) 3 times then release the UNLOCK button.
If done correctly the indicators should flash 2 times
3. To reprogram a further key/keyfob remove the key and put your second key in the ignition (or hold your fob close to the ignition barrel) leaving it in the LOCK position and repeat step 2.
Once done turn your ignition on and then back off to exit the coding procedure.
Test your keyfob(s) work ok. (do not leave your key in the car while doing this procedure incase you need to manually open the door with the key)

You are going to need to check the power lock control moduel on the inside of the door panel. If the FOB appears to be working but the doors are not unlocking, you need to check this. I would also replace all fuses that control the locks. If both of these devices check out ok, you may need to replace your FOB. To check your power lock control moduel, manually lock and unlock your doors by pressing the lock button on the inside of the door. If it does not work, it is either the fuses or the power lock control moduel. If it works, your FOB has gone bad. Hope this helps! Please rate 4 thumbs up!

Insert key into door barrel or ignition lock and turn key, whilst doing this press the unlock/lock button, the led on the dash should flash to indicate this has initialised the key to the car, then remove key and test operation of remote. If this fails then a new remote plus coding to the car by your dealership is needed

You should not have to reset the key fob after a battery replacement. The signal from the key fob stays the same and is programed to the reciever.
If the key fob needs to be reprogrammed then follow these steps.
1. Have all key fobs with you during programming.
2. Sit in the vehicle with all doors closed.
3. Lock all doors using the Lock/Unlock switch on the door.
4. Insert and withdraw the ignition key 7 to 9 times within 10 seconds (do not turn the key, just insert and withdraw).
5. The 4 way flasher indicator on the dash should flash once or twice.
6. Insert the ignition key and turn it on (key on, engine off).
7. Press any button on one remote and the 4 way flasher indicator on the dash should flash once.
8. If you have more key fobs to program use the Lock/Unlock button on the door to unlock the doors and then lock the doors.
9. Press any button on the next key fob and the 4 way flasher indicator on the dash should flash once.
10. Repeat if you have more key fobs. Only 5 can be programmed.
11. To exit, simply turn of the igniton and remove the ignition key.
12. Unlock the doors using the Lock/Unlock switch on the door and exit the vehicle.
13. Make sure the window is down when testing remotes in case you leave the keys inside.
14. Close all doors and test all remotes that were programmed.

Do not skip any steps or the process will not work.

If the 4 way flasher indicator does not work when inserting the key, you will need to start the process from the begining. If it still does not work the receiver may be your problem.

If the 4 way flasher indicator does not flash when pressing any button on the key fob then the key fob is the problem (dead battery or defective remote)

the keys needs to be initialised. put key in door lock or ignition barrel and press/hold the remote open button until led flashes on dash, release button and rremove key from lock, remote should now work

this is how most nissans program the key fobs.
get in the car and manually lock the drivers door with the door switch.
put the key in and out of the ignition about 10 or 12 times until the hazard lights flash once.
turn the key to the ignition setting so all the dash lights are on,but do not start the car.
click the lock button on the remote fob.the hazards should flash once to confirm.
turn off ignition and remove the key.
unlock the drivers door and open the door.
the remote should now work.
if that does not work,the dealer can reprogram the fob with the obd diagnostic system.

If it is a 2003 model year vehicle follow this procedure. If it doesn't work, you may have the wrong fob which happens all the time.

Sit in vehicle and close all doors.
COMPLETELY insert and remove ignition key more than six times within 10 seconds.
Hazard lights should flash twice.
Turn ignition to ACC position
Press and hold any button on the new key fob hazard lights will flash twice
For a second key fob using the master lock switch, lock and unlock the doors then hold down any button on the second remote until the hazard lamps flash twice.
Then you are done open the door to exit the programming mode.
If the lamps didn't flash when holding down the key fob make sure you have the right key fob, they are different for each car.

get into the car , close and lock all doors. insert your key into the ignition in and out 6 times or until your directionals flash. that's when the car is in program mode. you need to pay attention to it while putting key in and out of the ignition. watch your dash for flashing. its kinda hard, but you can do it. so just take your key and put it inside of the igniton and take it out 6 times in a row or until lights flash. when lights flash, put the key in the ignition and turn it to accesorries position (do not start the car). when the dash / cluster lights up after you turn the key, press any button on the remote. your hazards should flash on the dash again. after that happens, take the key out of the ignition and unlock the door with the door lock switch and open the door. remote is now programmed. congrats. you did it.