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Key fob failure - temporary?

JeffVanEpps

Member
Apr 1, 2015
73
13
When I went out to the parking lot tonight, Model S wouldn't let me in. I pressed the handles, waved the key around, nothing. I had to unlock it from my phone. Luckily it wasn't pouring rain or a blizzard, just cold. Got inside and it wouldn't let me start: "Key not inside car". Bah. Had to start it from the phone. It's less than 4 months old, shouldn't have a dead key battery yet. It never warned me about low battery. Got home, removed the battery, measured it: 3.0V. Took my second key fob (which I've never used) out to the garage, the handles presented properly. Replaced the battery in the 'bad' one with a fresh CR2032 and went out, same. Put back the 'bad' battery, went to the garage, and the handles presented. So I don't know what it's problem was earlier. :confused:
 

green1

Active Member
Mar 25, 2014
4,548
1,121
Calgary, Alberta, Canada
When I went out to the parking lot tonight, Model S wouldn't let me in. I pressed the handles, waved the key around, nothing. I had to unlock it from my phone. Luckily it wasn't pouring rain or a blizzard, just cold. Got inside and it wouldn't let me start: "Key not inside car". Bah. Had to start it from the phone. It's less than 4 months old, shouldn't have a dead key battery yet. It never warned me about low battery. Got home, removed the battery, measured it: 3.0V. Took my second key fob (which I've never used) out to the garage, the handles presented properly. Replaced the battery in the 'bad' one with a fresh CR2032 and went out, same. Put back the 'bad' battery, went to the garage, and the handles presented. So I don't know what it's problem was earlier. :confused:
maybe the fob needed a reboot?
 

green1

Active Member
Mar 25, 2014
4,548
1,121
Calgary, Alberta, Canada
A CR2032 is rated at 3V
That's correct, however with no load it could read higher than when in place in the fob, could be a dead battery, just because it's not that old, doesn't mean it's not dead, especially if it gets stored close enough to the car that it can communicate with it, this is known to kill the battery quicker.
 

JeffVanEpps

Member
Apr 1, 2015
73
13
How can I tell what's "close enough"? Normal resting place is about 25 feet from the car through the garage wall up up through the floor. In the same place, I didn't have this issue with the Prius key.
 

andreasmj

Member
Jan 5, 2015
26
17
Norway
The fob could have been jammed by transmitting devices in the area. I experienced this once in my car and it turned out my wireless door bell was stuck in "transmit"-position.
 

PaulR

Supporting Member
Feb 5, 2015
160
54
Atlanta, GA
I was having a similar problem with my fobs... erratic handle presentation. Sometimes it worked perfectly, sometimes I thought I was locked out. I had replaced the batteries in both fobs within the last two months so I don't believe that the problem was the batteries (they were very fresh). I also had one of those "keys not in the car" moments when stopped at a parking pay station. I had put the car into park while I reached into my pocket to get my wallet and the car would not let me put it back into drive. A very frustrating moment as those waiting in line behind me were wondering what was happening...... it finally allowed me to drive off. Probably some electronics in the parking pay station interfering?

I realized that I was keeping my BMW key in the same pants pocket as the fob. When I moved it to the other pocket it seems to work better, but still is erratic. Just for extra measure I replaced the battery also.

EMI and RF from other devices seem to be the biggest factor. We have so many devices surrounding us which give off interfering signals it's hard not to have something like this malfunction. My BMW X5 which is parked a few feet away from the Tesla I would guess that it is giving off RF, my WiFi which I use to update the car is doing the same, my two garage door openers are as well. Some on similar frequencies, some not, but Radio Frequency signals are ubiquitous.

Guess I would have to take my car out into the desert, without my other keys to test my theory. In the meanwhile it's anybody's guess as to whether I will be able to unlock my car the next time I want to use it.... :wink:
 

JeffVanEpps

Member
Apr 1, 2015
73
13
The fob could have been jammed by transmitting devices in the area. I experienced this once in my car and it turned out my wireless door bell was stuck in "transmit"-position.

Unlikely in this case. Alone in the middle of a parking lot where I've not had an issue in the past months.
 

green1

Active Member
Mar 25, 2014
4,548
1,121
Calgary, Alberta, Canada
How can I tell what's "close enough"? Normal resting place is about 25 feet from the car through the garage wall up up through the floor. In the same place, I didn't have this issue with the Prius key.
Probably far enough, but hard to tell for certain. Comparison to the Prius key isn't really valid as they just don't work quite the same way.
 

JeffVanEpps

Member
Apr 1, 2015
73
13
Probably far enough, but hard to tell for certain. Comparison to the Prius key isn't really valid as they just don't work quite the same way.

Well, any comparison a consumer cares to make is "valid". Would you say that it's not valid to compare 0-60 time between P85 and a McLaren F1 because they "don't work quite the same way"? People do compare them. And those comparisons are valid to them. Likewise we can compare key fob performance of Model S and Prius, regardless of whether or not they use the same technology. If we find that one of them needs to be housed in a box with 1-inch thick lead walls to avoid draining the battery in 1/4 the expected lifetime, that would be an important distinction, wouldn't it? (I'm not saying that's true). There is an implicit assumption that the two fobs should have equal lifetimes and shouldn't require any special care about where they are stored - it's just a key - just leave it in your coat pocket or toss it on the counter or whatever.

And they probably don't require any special care. Probably Tesla put a partially drained battery in this fob. We'll never know.
 

green1

Active Member
Mar 25, 2014
4,548
1,121
Calgary, Alberta, Canada
Well, any comparison a consumer cares to make is "valid". Would you say that it's not valid to compare 0-60 time between P85 and a McLaren F1 because they "don't work quite the same way"? People do compare them. And those comparisons are valid to them. Likewise we can compare key fob performance of Model S and Prius, regardless of whether or not they use the same technology. If we find that one of them needs to be housed in a box with 1-inch thick lead walls to avoid draining the battery in 1/4 the expected lifetime, that would be an important distinction, wouldn't it? (I'm not saying that's true). There is an implicit assumption that the two fobs should have equal lifetimes and shouldn't require any special care about where they are stored - it's just a key - just leave it in your coat pocket or toss it on the counter or whatever.

And they probably don't require any special care. Probably Tesla put a partially drained battery in this fob. We'll never know.
I didn't mean to imply that the customer experience isn't important, just that we can't say "the battery must be fine because the battery in the fob for my other brand of car is fine". It's a valid comparison for the stand point of how it SHOULD work, but not from the stand point of troubleshooting how it actually DOES work. Just like you can't take your prius to the mechanic and ask them to fix it because it can't accelerate as fast as the MS, you can't really get Tesla to "fix" your fob if the battery dies quicker than you'd like. That said, it would be good if Tesla's engineering worked on ways to fix it and offered upgraded hardware/software in the future.
 

sdick3

Member
Apr 26, 2015
18
0
Auckland, New Zealand
My car, Dec 2014, reported a low fob battery a week ago. I did not believe it and it went away.
Then recently auto present would not work, but pressing the handle opened the car.

Reboot both consoles and it's working again. Seems the on board computers need a reboot every now and then.

- - - Updated - - -

Oops I meant Dec 2015. So the fob is only a few months old so battery not flat.
 

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