Strange key fob remote entry behavior

[CharBaby]

After grocery shopping and walking our shopping cart to the car, I remote(key fob) started the car(Altima in sig) from the store exit. It started fine and I could see the lights flash. As I got closer to the car, I remote popped the trunk and it opened so I could load the groceries. Once loaded and shopping cart put in the parking lot cart corral, I remote unlocked my doors for my wife & I to get in running car. NOTHING! The door didn't unlock. So I did it again from the key fob and again, NOTHING!

I did however use the outer door handle buttons to enter the car and get in. All is well and I pressed the brake pedal & push button start to finalize my entry and then drove off and went home. OK? Are you with me so far?

One we got home and unloaded our groceries into the house(being about 5:30 pm), I locked up the car for the night with the key fob. NOTHING! It didn't lock the car. However I could walk up to the car, key fob in hand, and press the buttons on the door handles and all was well/locked up for the night.

The next morning, knowing my issue from the night before and using my key fob, I tried to unlock my car. NOTHING!
None of my key fob buttons worked including the RED emergency button. However, my extra set that my wife keeps, worked just fine.
I could still get in my car(carrying my key fob) and start the engine. As long as I kept the key fob with me, all was well except that none of the fob buttons worked.

Yesterday I got into my car and went to press the start button and got the dash banner stating NO KEY DETECTED. Well, I know that I have to hold the fob to the start button to gain communication. I did so and got the communication "BEEP" and proceeded to start the engine.

Now once again, my key fob buttons all work and everything is well and back to normal. However, I did try this procedure(holding the fob to the start button) when my fob buttons WERE NOT working but it didn't gain communication. Apparently, the key fob battery has to be low enough for the NO KEY DETECTED banner in the dash to appear, in order to gain communication.

I did remove the fob battery last week when this first happened and tested it(3.05v) and it was fine. What I needed to do was, keep the battery out of the key fob - go into the car - and show the fob to the start button to regain communication. Live & Learn!

 

[FowVay]

I remember years ago the key fob for my BMW stopped working. I just figured it was old and worn out so I just manually locked/unlocked the car. I had changed the battery and done the usual maintenance but never got it to work so I gave up.

Out of the blue and on a wild hair day I decided to get another battery and try it. Presto!!! The key fob has worked perfectly ever since.

So try a battery,,, or another battery. Get one of those TPMS tools that checks the key fob output and run it through its paces.

 

[Boomer]

On my VW All Track, the battery in my fob died and I bought a Duracell battery to replace it. Had all kind of weird issues. SO I stopped by the dealer. The parts guy atthe parts window opened it up and said the problem was the Duracell. Apparently they are just a tad thinner than others. He gave me a new battery free of charge and actually replaced it and the fob worked great ever after.

 

[CharBaby]

FowVay, thank you.
I did swap the battery with the other OE key fob that my wife holds for her use when she drives the Altima. They were both the same in terms of their volt measurement(3.05v) but, I did swap them anyway. These 3.0v #2032 batteries are typically ~3.20v when brand new.

At that time, swapping/changing the battery did NOTHING for my key fob. It was only when I had to touch the key fob the the push button start in the car. And ONLY when I got the banner in the dash(NO KEY DETECTED).

And as I mentioned, I did try touching the key fob to the start button in the dash however, there was no NO KEY DETECTED listed in the dash. So therefore, it still did not make/return the communication.

Typically the only time that I change(not swap) key fob batteries is when the volts drop below >2.90v-2.89v. This is when I notice that the fob just doesn't have enough juice to RES the engine or open the doors and I all too often get the NO KEY DETECTED upon starting the car with just the dash push button...you know?... get in the car, step on brake, push start button.

I do keep the key fob batteries(#2032) for my mountain bike speedometer/trip/miles(km)/calories that I use during the summer. So they don't go to waste.

 

[joekingcorvette]

At least you were not stranded. Those key fobs can be annoying at times.

 

[zzyzzx]

First world problems.

 

[PimTac]

I keep my fob procedure simple. I don’t use the automatic proximity function. When I get to the car I touch the button on the latch and everything unlocks. Same when leaving the car.

I believe a lot of these goofy foibles are due to the auto proximity functions.

 

[CharBaby]

thanks