The return of the missing key fob

[kofther]

When I first got my Bolt EV in April there were three separate occasions where the key fob was not detected and driver screen displayed "KEY FOB MISSING". After reading the forums there was a TSB that said have the RF module replaced. The dealer took care of it and this never happen again ... until this afternoon.

I went to my car and pressed the button on the handle to unlock the car. It unlocked the car which means it must have detected the fob however when I opened the door the horn started going off. I got in the car and used the unlock button on the fob and the horn stopped. So again I assume the fob communicated with the car. I pressed the start button and that was when I got the key fob missing message. It instructed me to place the fob in the bottom of the center console. I emptied the center console, placed the fob in the bottom and it was detected.

Maybe there are separate radios for the locks vs. the engine functions? All I was thinking was I was going to have to get towed home. I'd like to take this to the dealer but whats the chance they can track down this intermittent issue?

-Kof

 

[grestep5621]

I had the same problem and hitting the physical home and Fast Forward buttons until the screen rebooted fixed it.
I tried many other combinations of solutions, but a reboot fixed it.
It seems to happen when the linux OS that runs the console is having issues.
I also know that the bluetooth radio in the console has issues that require the console to be rebooted to fix.
I now reboot the console whenever the bluetooth doesn't connect at first try and so far the key fob issue hasn't returned.
My guess is that like any linux system (it may be a specialized version, but it seems to be linux under the covers, it takes a reboot to get back to a known state.
I also reboot my cellphone as the Android system seems to have issues connecting to the car occasionally and a reboot fixes that also.

 

[kofther]

Thanks. I'll give the infotainment reboot a try when it happens again. I had this done and thought that would be the end of it but I guess not.

#16-NA-396: Intermittent Operation of Key Fobs, Door Unlock Inoperative “No Remote Detected” Message with Possible TPM MIL - (Jan 19, 2017).

 

[dandrewk]

I had the exact same sequence happen to me... twice, and in the exact same spot in the same parking lot. Unlock door, car chirps like the alarm is about to sound, then alarm sounds. Push unlock button on fob to turn of alarm. Bolt won't start, asking to put fob underneath the tray in the arm rest. Car starts, everything back to normal.

It hasn't happened for a couple of months, so I attributed it to some RF interference in that particular spot. If you are driving home or going anywhere where the Bolt will be parked and off for five minutes, no need to reboot infotainment as issue goes away by itself.

 

[user 1340]

Note that the Key FOB turning off the alarm is not the same tech as the car detecting the FOB for ignition operation.

Hitting the unlock button sends an RF signal to the BCM. The BCM still doesn't know where the FOB is. It could be 30 meters away.

When you press the ON button, the car uses a low frequency (LF) signal to check that the FOB is inside the car. THIS is the signal that is failing and it is why you have to put the FOB in the armrest pocket when the FOB battery dies. This LF signal comes from a different antenna and the FOB has to respond.

Either the FOB's LF antenna/circuitry is acting up (low battery, perhaps?) or the car's LF transmitter or PEPS (Passive Entry Passive Start) module/antenna is the problem. FOB batteries should be dying this early. They should be good for 2-3 years, but they are easily swappable.

Interference of the LF signal is possible.

It's all still under warranty at this point. I haven't had this problem at 2000 miles, yet.

 

[dandrewk]

Note that the Key FOB turning off the alarm is not the same tech as the car detecting the FOB for ignition operation.

Hitting the unlock button sends an RF signal to the BCM. The BCM still doesn't know where the FOB is. It could be 30 meters away.

When you press the ON button, the car uses a low frequency (LF) signal to check that the FOB is inside the car. THIS is the signal that is failing and it is why you have to put the FOB in the armrest pocket when the FOB battery dies. This LF signal comes from a different antenna and the FOB has to respond.

Either the FOB's LF antenna/circuitry is acting up (low battery, perhaps?) or the car's LF transmitter or PEPS (Passive Entry Passive Start) module/antenna is the problem. FOB batteries should be dying this early. They should be good for 2-3 years, but they are easily swappable.

Interference of the LF signal is possible.

It's all still under warranty at this point. I haven't had this problem at 2000 miles, yet.

Very useful info, thanks!

I think you are correct re: LF signal interference, as it's happened to me in the exact same spot in the same parking lot.

But I still find the sequence curious: I use the door handle to unlock, which is does. Immediately the Bolt starts chirping like the alarm is about to go off, which it does. I cancel the alarm with the FOB button, and then have to place it in the glove box to start the car. Question: Why does the car allow me to unlock the vehicle and then behave like I'm breaking in?

 

[user 1034]

...I use the door handle to unlock, which is does. Immediately the Bolt starts chirping like the alarm is about to go off, which it does. I cancel the alarm with the FOB button, and then have to place it in the glove box to start the car. Question: Why does the car allow me to unlock the vehicle and then behave like I'm breaking in?

I think it is a "redundancy of systems" thing. These two major components have different systems in order to prevent total failure if one component goes.

In the case of the radio going out and only being able to confirm at close range, you can still at least get in the car and drive.
The other, at least you have a physical key to still get in the car and drive.

 

[user 1340]

Very useful info, thanks!

I think you are correct re: LF signal interference, as it's happened to me in the exact same spot in the same parking lot.

But I still find the sequence curious: I use the door handle to unlock, which is does. Immediately the Bolt starts chirping like the alarm is about to go off, which it does. I cancel the alarm with the FOB button, and then have to place it in the glove box to start the car. Question: Why does the car allow me to unlock the vehicle and then behave like I'm breaking in?

That's a good one. I've yet to figure it out as the unlock should have disarmed the alarm to open the door.

 

[gpsman]

I never had this happen in the first 6 months and 6200 miles.

Then I went to the dealer for the software update.
Then 2 days later this happened to me.

And we had BOTH keyfobs.
Neither one would be rrecognized or let the car start.
And it happened at the worst possible time.

My wife was very ill and I was trying to rush her to the E.R. Not a good time to fumble around and try to learn a new process.

CHEVY I AM NOT AMUSED BY ALL THE SOFTWARE ISSUES.

 

[Tetondoc]

I've had this happen twice. Once on first day I owned the car. Second time about a week ago. Unlocked door with the button on the door handle. Got in car and pressed on button. Both times it occurred I had unplugged it from charger before getting in. I've never had it happen when car was not plugged in. I have the "cord theft" alarm turned OFF. I got initial "chirp" on horn then full "car alarm" going off. Using keyfob to lock then unlock the car turns the alarm off, and then able to go on my way.

I have two theories...
1) May be related to having been plugged in to charger and timing of removing charge cord, then unlocking and starting car? Occurs even though "cord theft alarm" is turned OFF.
2) Possibly a timing issue of unlocking car then turning it on too quickly, before the computer boots up or before RF has time to recognize the keyfob is in the car?

I agree... frustrating.

 

[gpsman]

In my case I was no where near a power plug.
So it's not related to the charge cord.

 

[JAL1]

I found this useful video on another discussion:

https://youtu.be/ILFYhMcnynE