Put brand new battery in key fob for car, fob still not working.

[slackmax]

2009 Nissan Versa.

Have been using the actual key, not the fob, for last 5 years, since fob stopped working to lock and unlock doors. 

Today, thought I would put new battery in fob, see what happens. New battery in, and still doors do not lock or unlock with fob. 

Tested new battery with multimeter. It is supposed to be  3 volts, and is slightly over 3 volts, so all good there.

New battery is installed correctly, positive side down.

No corrosion on terminals noted.
 
Is there something above and beyond replacing the battery that I am supposed to do to get the doors locking and unlocking again with the key fob?

Thanks

edit to add:  this fob isn't for starting the car, it's just for locking, unlocking, and sounding an alarm. Simple stuff.

[Sibley]

https://batteryglobe.com/nissan-key-fob-not-working-after-battery-change/

Any of that help?

[cool7hand]

We had a tough time fixing our FOB through a locksmith. With the benefit of hindsight, we'd just go to a dealer.

A couple of years ago with our tow vehicle, a 2010 Nissan Pathfinder, one of our two FOBs stopped working. Apparently there are some settings to get your car, and not some other Nissan, to talk to the FOB. Our FOB had two transponders: one that worked at about 20 feet for the doors; and one that worked at about 3-6 feet for the ignition. The FOBs internal settings can flake either for lack of power for a long period of time, a power surge to the car, dropping the FOB, etc. Our options were to have the dealership or a locksmith reprogram the FOB with some proprietary machine. The locksmith cost only half what the dealer did, so we went with the locksmith. The locksmith fixed the FOB, which worked great, but only for a few months. Then the door transponder stopped working. The locksmith fixed it, but got nasty when I refused to pay. A few months later, the distance transponder stopped working again. The locksmith wanted money up front to fix it and refused to negotiate, so we left an honest review in multiple places about our experience. We were already in the process of selling it, and the second FOB working imperfectly did not affect the purchase price.

If we had it to do over again, we'd just go to the dealer and pay double to avoid all the hassle.

[Dicey]

We had a tough time fixing our FOB through a locksmith. With the benefit of hindsight, we'd just go to a dealer.

A couple of years ago with our tow vehicle, a 2010 Nissan Pathfinder, one of our two FOBs stopped working. Apparently there are some settings to get your car, and not some other Nissan, to talk to the FOB. Our FOB had two transponders: one that worked at about 20 feet for the doors; and one that worked at about 3-6 feet for the ignition. The FOBs internal settings can flake either for lack of power for a long period of time, a power surge to the car, dropping the FOB, etc. Our options were to have the dealership or a locksmith reprogram the FOB with some proprietary machine. The locksmith cost only half what the dealer did, so we went with the locksmith. The locksmith fixed the FOB, which worked great, but only for a few months. Then the door transponder stopped working. The locksmith fixed it, but got nasty when I refused to pay. A few months later, the distance transponder stopped working again. The locksmith wanted money up front to fix it and refused to negotiate, so we left an honest review in multiple places about our experience. We were already in the process of selling it, and the second FOB working imperfectly did not affect the purchase price.

If we had it to do over again, we'd just go to the dealer and pay double to avoid all the hassle.

Lol, my spare went missing for over well over a year. For my birthday last year, I asked DH for a replacement. He took a similar DIY path. It ended up being a lot of hassle and cost more than planned. We still spent $200-300 less than the dealer wanted. The new fob works, but is less responsive than the factory one.

Last week, I dropped something under the bed. I couldn't see anything, even with a flashlight, so I was groping around blindly.  I felt something wedged between the leg of the bed and the baseboard. Sure enough, it was the long-lost key fob. Arrrgh!

[slackmax]

https://batteryglobe.com/nissan-key-fob-not-working-after-battery-change/

Any of that help?

Sibley, thanks for the link, but I can't open it for some reason, probably a glitch on my side.

[slackmax]

Thanks, Wow, interesting FOB stories! Amazing what a pita they are.

I have been using my key alone to lock and unlock the car for years now, but was starting to wonder if I were wearing out the door lock, therefore wanted to offload that task to the FOB.

Interestingly, there is only one door which has a keylock on it! The driver door. If that lock gets messed up, I can't just use another door. I guess I could leave the car unlocked. ( Nope, lol)         

I think, given the new info about FOB difficulty and expense, I'll just keep on keeping on with my metal key, and be gentle, and try not to wear anything out too soon, lol. Maybe spray some graphite in there.

[BudgetSlasher]

https://batteryglobe.com/nissan-key-fob-not-working-after-battery-change/

Any of that help?

Of those number 7 jumps out at me.

#7: Your key fob has lost its memory
When you change your key fob battery, you need to fit the new one quickly. If the battery is left out for around 30 seconds or more, the key fob can lose its memory.

If this happens, you will need to follow the procedure below to reprogram the fob.

6 Steps to Programming Your Nissan Key Fob:

Get into the driver’s seat of your Nissan.
Lock the doors using the lock doors button on the control panel.
Within 10 seconds, insert and remove the ignition key. If successful, the vehicle’s interior and exterior lights will flash. If nothing happens, start again, as the timing is essential here.
Now insert the ignition key and turn it to the first position to select the ACC mode.
Press any key on the key fob once. Your hazard lights will flash once, indicating that the key fob is being reprogrammed.
Wait for around 10 seconds, then remove the ignition key, get out of the car and try to use the key fob. It should now work correctly, but if not, repeat the process.

Since the TS has been using the key for 5 years since the fob stopped working, I wouldn't be surprised if the battery went from weak to totally dead and this is what happened.

[lthenderson]

Here is a good short video on reprogramming a fob for a Nissan Versa.

https://www.youtube.com/watch?v=qnZ7OM66Gvc

[slackmax]

Hey guys, thanks for the links. I was finally able to get into them all. The youtube one was very useful. 

I made a stab at reprogramming the fob, by inserting the key 8 times in 10 seconds, but the lights didn't flash like they are supposed to.

I got scared about disabling my car in the middle of winter, unnecessarily, and stopped all progress at that point.

By the way, the little red car icon under the spedometer started flashing too! But it urns out that it is supposed to be flashing at times, so I stopped being concerned  about that. Probably I just never noticed it before, lol.

So I will maybe try again in the Spring.     Leaving well enough alone for now, don't fix it if it ain't broke, etc, lol.       (ain't broke meaning the actual metal key still works fine for everything)   

[jeromedawg]

I might have missed it but do you have a second fob? And does it work?

If the car battery is good and you put a fresh battery into the fob, then it's either the fob itself (where the onboard electronics have shorted - has the key fob ever been dunked in water/saltwater?) OR the transponder on the car that has gone bad... or possibly a blown fuse? You might be able to have a mechanic potentially check for blown fuses if you don't know how yourself.

[slackmax]

I might have missed it but do you have a second fob? And does it work?

If the car battery is good and you put a fresh battery into the fob, then it's either the fob itself (where the onboard electronics have shorted - has the key fob ever been dunked in water/saltwater?) OR the transponder on the car that has gone bad... or possibly a blown fuse? You might be able to have a mechanic potentially check for blown fuses if you don't know how yourself.

Yes, I have a second fob. You didn't miss anything. I just didn't want to muddy the waters. But since you asked: 

I tried the second fob with its original battery. Didn't work. Tried putting in a new battery. Still didn't work. (Even after doing the 'insert key 8 times in 10 seconds' trick)

The second fob is my backup fob, and therefore has hardly ever been used.

I tested both primary and backup fob original batteries and they were both slightly over 3 volts, which is exactly what they are supposed to be.

Primary fob has 2 contact points inside that are quite worn. I thought that might be the problem.  But backup fob has no wear on the same contact points. And backup fob, even with new battery, does not work.

I think what happened is that both batteries are low in some way, due to age,  even though still showing 3 volts on multimeter.

I read somewhere that even if the battery shows 3 volts, the voltage drops a lot when a draw is placed upon it, and therefore is too low when it is needed.

Also something about 'amperage' not being high enough even though volts are high enough.   

I read that the 'code' programmed into the fob's memory will disappear if the voltage is too low, or amperage or whatever, and that that is when you need to go through the antics to get the car's transponder to send the code to reload the fob memory. Seems like an overthink by the designers, lol. Why not have the code hardened into the memory circuit (rom) ?   

Blown fuse? OK, will check it.

FOBs have not been abused in any way.

The car had an electrical harness spliced at one time, but I don't recall the FOB not working then.

[lthenderson]

I would suspect your car has a rolling code in it for security purposes, i.e. to prevent somebody nearby from copying the code through the air and then using it to enter your car after you are gone. These are pretty standard these days. With a rolling code, if the codes between the car and the fob get too far out of synch, it requires them to be resynched to work again. My guess is that after five years of non-use, this is what happened and has nothing to do with battery status and you pretty much confirmed this when you put in a new battery and it didn't work.

Also, that video link I sent you stated 8 to 10 times when inserting the key but watching the video he did it I think 12 times before the lights flashed so be aware of that.

[slackmax]

Thanks, LT !

[zolotiyeruki]

Interestingly, there is only one door which has a keylock on it! The driver door. If that lock gets messed up, I can't just use another door. I guess I could leave the car unlocked. ( Nope, lol)         

Let me guess, a GM product?  (I recently had a car like that.  Holy cow, what a terrible engineering decision!)

I think what happened is that both batteries are low in some way, due to age,  even though still showing 3 volts on multimeter.

I read somewhere that even if the battery shows 3 volts, the voltage drops a lot when a draw is placed upon it, and therefore is too low when it is needed.

Also something about 'amperage' not being high enough even though volts are high enough. 

Having just gone through exactly this scenario this week, you are correct here--a battery can show enough voltage when unloaded, but its internal resistance can prevent it from powering anything.  A fresh battery helped.

(I also mess with electronics as a living, so I replaced the buttons on the circuit board in our failed fob.)

It sounds like you need to do all the hokey-pokey of programming your fobs to work with your car again.