Key Fob Weirdness

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Bombastinator2

Well-known member
Joined
Jan 3, 2024
Messages
295
Why is there a cut key inside my fob? There are no keyholes on the car. Also, why does the thing read “no key detected” after i change the battery? It’s like i killed by key by changing the battery. Gonna have to use my spare.

UPDATE: spare worked fine. Battery was literally new out of the package though. I opened it to check if the thing was in the right way, it was, I suppose I can get ANNOTHER battery and try that b it it doesn’t seem likely to work to me. I’ve never heard about 2025s discharging in the package. The package is old though.

2nd UPDATE:
replaced the button battery and all is good now
 
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What year is your Leaf? Our 2014 definitely has a key slot, at least in the driver's door.
The coin batteries should last a long time, but I suppose it's possible to buy a dud. Where you rough when you snapped the key fob open and closed? I've seen them get damaged from aggressive prying.
 
Interestingly, name brand batteries are one of the most counterfeited items on the Internet. Places like Amazon are filled with skillfully copied AA, AAA, coin cells, and even specialty sizes like A23. Try to only buy batteries in local stores like national chain drugstores and hardware stores. You can also try dollar stores, but the odds there are closer to those when you buy online. That being said, I've had excellent luck with my local dollar store - or maybe I've just gotten good counterfeits..
 
What year is your Leaf? Our 2014 definitely has a key slot, at least in the driver's door.
The coin batteries should last a long time, but I suppose it's possible to buy a dud. Where you rough when you snapped the key fob open and closed? I've seen them get damaged from aggressive prying.
2019sv. I did buy the 2025s from Menards though which is by far the lowest end of the big box retailers. They have some of the tackiest concrete lawn ornaments I’ve EVER seen there and I was personally ripped in zippy the pinhead for giving a concrete lawn ornament fountain to the driveway contractor. They might have sold me crap. They do it enough with lumber. (Never buy lots of lumber there btw. Look at EVERY PIECE. They tend to uprate the quality of the lumber and you may find more than a few unusable pieces)

I tested the new battery. It would run the “senile old man lost his car in the parking lot again” horn thing, and it would lock and unlock the doors. I kept getting a “No key detected” warning though. I wonder if I’ve got a lead-acid 12v in there. Gonna check.
 
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IMG_1674.jpegThis is my 12v. It might be crap too. They sold the thing to me with summer weight tires on it so it wouldn’t surpise me that if it had a decent battery they pulled it and put in junk
 
Open the hood, let the car sit 30 minutes with all doors shut, then test the voltage at the 12 volt battery terminals. Do NOT open the doors until you re done. Anything over 12.25 volts should eliminate the battery as a culprit. Anything over 12.4-12.5 volts indicates a likely decent battery.
 
Open the hood, let the car sit 30 minutes with all doors shut, then test the voltage at the 12 volt battery terminals. Do NOT open the doors until you re done. Anything over 12.25 volts should eliminate the battery as a culprit. Anything over 12.4-12.5 volts indicates a likely decent battery.
Will do. Looking at the battery, it’s apparently lead acid (as it has that bit on top which implies it, and it seems weirdly narrow, though apparently the standard size. Makes me suspect it was designed to have a LiFePO4 battery in it but they pulled it to screw me. Like the tires. That one cost me when i slid into a bus because they had no business being on snow.
 
The OEM battery is old timey lead acid but "weirdly narrow" because it doesn't need to power a starter motor like in an ICE car so a smaller one is enough.
 
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The OEM battery is old timey lead acid but "weirdly narrow" because it doesn't need to power a starter motor like in an ICE car so a smaller one is enough.
The Battery is a Group 51R same is used to start ICE Asian vehicles, my diesel tractor and a old Saab. Nissan used it because it IS a standard off the shelf battery.
 
The OEM battery is old timey lead acid but "weirdly narrow" because it doesn't need to power a starter motor like in an ICE car so a smaller one is enough.
So i was looking at amazon just in case. So a 50amph LiFePO4 battery would do it or do i need 100amph? It seems i can get them both in group 51R
 
Amazing how these posts get off topic so quickly. Started off discussing key fob batteries, and got moved off to 12 volts. Doesn't anyone pay attention? At any rate, I note that it was mentioned that fob batteries were being replaced with 2025's. Why don't you put in a 2035? Fits perfectly, and lasts much longer.
 
Amazing how these posts get off topic so quickly. Started off discussing key fob batteries, and got moved off to 12 volts. Doesn't anyone pay attention? At any rate, I note that it was mentioned that fob batteries were being replaced with 2025's. Why don't you put in a 2035? Fits perfectly, and lasts much longer.
Incidentally, my 2019 SV+ has a key slot in the drivers door handle.
 
So i was looking at amazon just in case. So a 50amph LiFePO4 battery would do it or do i need 100amph? It seems i can get them both in group 51R
What is you location and climate? Like the cars traction battery, LiFePO4 also have freezing temperature problems. Unless you're planning on adding a battery warmer.
 
Amazing how these posts get off topic so quickly. Started off discussing key fob batteries, and got moved off to 12 volts. Doesn't anyone pay attention? At any rate, I note that it was mentioned that fob batteries were being replaced with 2025's. Why don't you put in a 2035? Fits perfectly, and lasts much longer.
Didn't you hear? Replacement of the 12 volt battery cures ALL Leaf problems! Traction battery has a bad cell? replace the 12 volt, key will not unlock the car, replace the 12 volt! Got a flat tire? replace the 12 volt, and if you use a Lithium 12 volt you tires will never go flat!
 
Amazing how these posts get off topic so quickly. Started off discussing key fob batteries, and got moved off to 12 volts. Doesn't anyone pay attention? At any rate, I note that it was mentioned that fob batteries were being replaced with 2025's. Why don't you put in a 2035? Fits perfectly, and lasts much longer.
I think you mean a 2032 battery and it is slightly thicker than the 2025, .7mm, but I'm sure should work and if you say it fits perfectly I'll take your word for it.

I did recently get a warning on the dash that it was time to replace the fob battery in my 2022 SV, which was a little over a year old with light usage, and thought about using one of the 2032's I had available, but also had a 2025 so went ahead with it. Like you say, the 2032 will last longer and of course is the same voltage. I always check a new battery with a volt/ohm meter before replacing.

I've been using the Sunbeam brand 2032 battery sold at the Dollar Tree Stores for many years and have never had a issue with them, 3pk for $1.25.
 
The extra thickness of 2032 cells can be problematic. Some owners have had it cause fob issues in the past. If the fob were designed for that thickness they'd spec 2032. It's not like they specified an undersized battery for the lulz. Actual battery dimensions can differ from the spec so YMMV.
 
UPDATE: spare worked fine. Battery was literally new out of the package though. I opened it to check if the thing was in the right way, it was, I suppose I can get ANNOTHER battery and try that b it it doesn’t seem likely to work to me. I’ve never heard about 2025s discharging in the package. The package is old though.

If the spare works then a good test would be to test that known good battery in the problem fob.
 
I just went through a key fob battery replacement exercise. New Duracell 2025 did NOT work! Rayovac 2025 did. I expect it's a physical issue where the Duracells are not making proper electrical contact. The fob was dead with the Duracells and, yes, I did check them for proper voltage using a battery tester.
 
One should always check a new FOB's battery output current by using a VOM set to the highest milliamp scale.
Typically, a 2025 battery should provide at least 200ma.
 
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