Key Fob went to sleep
01-16-2023, 09:50 PM
#1
Member
Thread Starter
Key Fob went to sleep
This is a 2021 GLS450 that I've owned for about 3 weeks.
I had an issue last week and I'm puzzled. I was in the carpool line waiting for my daughter for 20-25 minutes. I had the windows down. I had gotten out and walked around the vehicle a couple of times to get my other daughter a snack. When it was time for the line to start moving I had been sitting in the drivers seat for 10 minutes. I pushed the start button and everything came on as normal except the engine didn't start (no warning lights on the dash). I tried a couple more times with no change. I then tried to shift into gear thinking that would cause the engine to start, but it did not. I pulled the key out of my pocket and locked/unlocked the doors and tried again with the same results. The only difference was once it told me to press the brake to start (my foot was on the brake) and another time it told me to press the brake to shift into gear (again, my foot was on the brake). At this point I called the dealership and they put me on with their tech guy. He had me try several things including putting the key in the slot in the console. None of this made any difference. By this point the service department recommended a tow. While they were setting this up my wife arrived and tried with her key, but it would not work either (I was about 10 feet from the vehicle during this). I was sitting in my truck with my wife waiting to hear from the wrecker and decided to walk back over to the GLS and try it one more time and it started right up. This was 45 minutes from when the problem initially began. I drove it to the dealership and left it for them to look at.
After a couple of days all they could come up with was that my key had gone to sleep and that my wife's key wouldn't work because the GLS was locked on to my key even though it was asleep. This didn't make sense to me, but I'm not a Mercedes technician. Since then I have done some research on the key going to sleep and it doesn't fully add up to what I experienced. I would think me walking around the vehicle every 5-10 minutes would have kept my key awake. Also, the locking/unlocking and other things the tech guy at the dealer had me try should have woken it up as well. Also, walking to and from the GLS several times to get items should have woken it up much sooner than it did. Is there something else that would explain what happened? Is there some other way to ensure the key is awake? The battery in the key was only a few weeks old. Also, would the windows being down affect the way the vehicle acts? At one point the dealer said it did, but they couldn't explain how when I asked.
My concern is that this was the second time using the GLS in carpool and this will happen 5 days a week. I envision this being a common problem if the key indeed went to sleep and Mercedes suggestions for waking the key up did not work. I feel like there has to be something else going on or there is another way to wake the key up and was not mentioned to me.
I had an issue last week and I'm puzzled. I was in the carpool line waiting for my daughter for 20-25 minutes. I had the windows down. I had gotten out and walked around the vehicle a couple of times to get my other daughter a snack. When it was time for the line to start moving I had been sitting in the drivers seat for 10 minutes. I pushed the start button and everything came on as normal except the engine didn't start (no warning lights on the dash). I tried a couple more times with no change. I then tried to shift into gear thinking that would cause the engine to start, but it did not. I pulled the key out of my pocket and locked/unlocked the doors and tried again with the same results. The only difference was once it told me to press the brake to start (my foot was on the brake) and another time it told me to press the brake to shift into gear (again, my foot was on the brake). At this point I called the dealership and they put me on with their tech guy. He had me try several things including putting the key in the slot in the console. None of this made any difference. By this point the service department recommended a tow. While they were setting this up my wife arrived and tried with her key, but it would not work either (I was about 10 feet from the vehicle during this). I was sitting in my truck with my wife waiting to hear from the wrecker and decided to walk back over to the GLS and try it one more time and it started right up. This was 45 minutes from when the problem initially began. I drove it to the dealership and left it for them to look at.
After a couple of days all they could come up with was that my key had gone to sleep and that my wife's key wouldn't work because the GLS was locked on to my key even though it was asleep. This didn't make sense to me, but I'm not a Mercedes technician. Since then I have done some research on the key going to sleep and it doesn't fully add up to what I experienced. I would think me walking around the vehicle every 5-10 minutes would have kept my key awake. Also, the locking/unlocking and other things the tech guy at the dealer had me try should have woken it up as well. Also, walking to and from the GLS several times to get items should have woken it up much sooner than it did. Is there something else that would explain what happened? Is there some other way to ensure the key is awake? The battery in the key was only a few weeks old. Also, would the windows being down affect the way the vehicle acts? At one point the dealer said it did, but they couldn't explain how when I asked.
My concern is that this was the second time using the GLS in carpool and this will happen 5 days a week. I envision this being a common problem if the key indeed went to sleep and Mercedes suggestions for waking the key up did not work. I feel like there has to be something else going on or there is another way to wake the key up and was not mentioned to me.
01-16-2023, 11:08 PM
#2
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Sounds odd, and I'd want a cause and effect identified before I was comfortable.
Was your car running or not, when you walked around the car while waiting?
If running, the car will sense that you're not inside, and start making bonging sounds, looking for you. It might not let you drive away or put it in gear.
Was it running but just doing Start-Stop?
Maybe you got caught in some "where's the key" algorithm.
Anyway, part of any troubleshooting for me, includes turning off the ignition after completing an action, then opening and closing the driver's door. As if you got out and reentered. The Welcome screen should appear when you have done this.
If they didn't have you open and close the door, try it. Good luck.
Was your car running or not, when you walked around the car while waiting?
If running, the car will sense that you're not inside, and start making bonging sounds, looking for you. It might not let you drive away or put it in gear.
Was it running but just doing Start-Stop?
Maybe you got caught in some "where's the key" algorithm.
Anyway, part of any troubleshooting for me, includes turning off the ignition after completing an action, then opening and closing the driver's door. As if you got out and reentered. The Welcome screen should appear when you have done this.
If they didn't have you open and close the door, try it. Good luck.
01-17-2023, 02:10 PM
#3
following as this happened on 2022 GLS.
drove car out of garage, turned off engine and open hood with key fob in pocket. spent 5-10 minutes outside of the car and attempted to restart to drive back in. all lights came on but engine wouldn't start. received same notice (put foot on brake and shift into gear) while attempting to start. tried second key fob with no luck.
spent 15-20 minutes inside house researching possible options. went back outside and somehow it started.
48v issue creeping in?
drove car out of garage, turned off engine and open hood with key fob in pocket. spent 5-10 minutes outside of the car and attempted to restart to drive back in. all lights came on but engine wouldn't start. received same notice (put foot on brake and shift into gear) while attempting to start. tried second key fob with no luck.
spent 15-20 minutes inside house researching possible options. went back outside and somehow it started.
48v issue creeping in?
01-17-2023, 08:51 PM
#4
Member
Thread Starter
following as this happened on 2022 GLS.
drove car out of garage, turned off engine and open hood with key fob in pocket. spent 5-10 minutes outside of the car and attempted to restart to drive back in. all lights came on but engine wouldn't start. received same notice (put foot on brake and shift into gear) while attempting to start. tried second key fob with no luck.
spent 15-20 minutes inside house researching possible options. went back outside and somehow it started.
48v issue creeping in?
drove car out of garage, turned off engine and open hood with key fob in pocket. spent 5-10 minutes outside of the car and attempted to restart to drive back in. all lights came on but engine wouldn't start. received same notice (put foot on brake and shift into gear) while attempting to start. tried second key fob with no luck.
spent 15-20 minutes inside house researching possible options. went back outside and somehow it started.
48v issue creeping in?
01-18-2023, 10:02 AM
#5
I'm just going to throw out an idea. I had a very similar experience with a 2013 Nissan Pathfinder years ago. It turns out it was a faulty brake relay. The vehicle wouldn't start because it thought my foot was not on the brake. Might be worth a shot to look in to.
The following 2 users liked this post by marz989:
nextmilenium (01-19-2023),
ricardo124 (01-18-2023)
01-19-2023, 06:53 PM
#6
Senior Member
My key goes to sleep all the time when I’m driving. When I get out and try to lock the doors by touching the button on the door handle, it doesn’t work. If I then reach done and just giggle the key a little in my pocket, the door locks work. My point of this is that it doesn’t really take much motion to bring a key out of sleep mode. Certain the various steps you took based on the dealer’s advice had the key awake - IF the system was working properly.
