Key Not detected when underway- intermittent

[CKiefer]

"Key not detected. Unable to restart after this drive..."

Since getting the recent MMC upgrade I started receiving this message intermittently but frequently once I was driving the car even though I started the car without problems and did not receive the message before being underway. This problem was coincident with this upgrade, occurred with both key fobs and I never had it for the previous 7 years. It must be the upgrade, right? We replaced the key battery and Tesla service center ran all its tests and they showed normal. They also said that they have installed thousands of upgrades and have not had this as a reported issue. A mobil service technician ran several resets, also to no avail.

I stumbled on something that might help if you are encountering this problem. Lacking a right, back pocket in my sweat pants I have been keeping my wallet (with cards) and the key fob inside my right front pocket with the key fob outside the wallet, i.e. between the wallet and the center console. The slightest direct touch on the key fob causes the alert to go away. I've stopped keeping the key fob and my wallet in the same pocket and the problem hasn't yet reoccurred. Maybe it's some sort of interference between the credit cards and the key fob.

I'd be curious if others have had this problem and whether this solution works.

 

[PCMc]

I learned very early on that I needed to be careful about keeping my key fob in the same pocket as my iPhone. Typically no issue if I keep the key fob on the outside, more likely if things get shifted and the phone on top of the fob. I also have started more taking my phone(s) out of my pocket and laying them in the center console when I drive. That's due to having elected to finally accept having a separate work and personal mobile phone and having two phones in my pocket just feels too bulky when I'm driving.

Given the number of rfid type of credit cards, etc., it's not impossible that something with your wallet is causing interference. Any chance you happened to get a new credit card or something in the wallet about the same time?

 

[DerbyDave]

Touching the key fob makes your body extend the range like an antenna. I used to hold my key fob up to my chin when unlocking other cars I own to increase the range. It works. My 2020 had issues like this whenever I was charging my Samsung phone in the Tesla wireless charger. Tech support said the phone was causing interference with the key fob receiver in the center console near the phone charger. Removing the phone from the charger solved this issue, and it doesn't cause any issues when I am sitting in the car to get the warning while it is charging.

 

[teslick2]

"Key not detected. Unable to restart after this drive..."

Since getting the recent MMC upgrade I started receiving this message intermittently but frequently once I was driving the car even though I started the car without problems and did not receive the message before being underway. This problem was coincident with this upgrade, occurred with both key fobs and I never had it for the previous 7 years. It must be the upgrade, right? We replaced the key battery and Tesla service center ran all its tests and they showed normal. They also said that they have installed thousands of upgrades and have not had this as a reported issue. A mobil service technician ran several resets, also to no avail.

I stumbled on something that might help if you are encountering this problem. Lacking a right, back pocket in my sweat pants I have been keeping my wallet (with cards) and the key fob inside my right front pocket with the key fob outside the wallet, i.e. between the wallet and the center console. The slightest direct touch on the key fob causes the alert to go away. I've stopped keeping the key fob and my wallet in the same pocket and the problem hasn't yet reoccurred. Maybe it's some sort of interference between the credit cards and the key fob.

I'd be curious if others have had this problem and whether this solution works.

There are multiple fob sensors in and around the car. Maybe one wasn’t reattached correctly after the install?

 

[DerbyDave]

The only fob sensors that would be of concern are the ones to determine if the key is inside the vehicle.

 

[cmarshack]

My 2020 Model S Long Range would give me this message every day, about 1 minute after driving. I assume the car initiates a "key check" shortly after you drive away.

For me, it was the combination of my phone always being in the OEM Wireless Charger (I always put it in there as soon as I get into the car) and my key always bing in my right hand pocket. My assumption was that the electromagnetic interference of the wireless charger coil big in close proximity of the key, would not allow the car to "see" the key during that initial key check.

All I would do, is pull the phone out of the charger for a second and put is back in, this worked every time.

The fix would be for Tesla to cut power to the charger at the same time it validated the presence of the key. But that is probably too much to ask.

 

[Huachipato]

I started getting the alerts recently. Mine did not coincide with the MCU2 upgrade - since that was done months ago. I suspect since I haven't really changed anything, and the "Key fob battery low" message seems to come up instead every once in a while, that it may be a fob battery that just needs replacing.

 

[DerbyDave]

My warning has gone off in the middle of driving, when I put the phone in the holder to charge, not just when I start to drive. I believe if you place the key just under the 12V accessory plug in the console tray, the warning will not happen. This is also an area you can place the key when the battery is dead in the key fob, and still drive, as well as where you place the key fob to update its code.

 

[SoCal Buzz]

"Key not detected. Unable to restart after this drive..."

Since getting the recent MMC upgrade I started receiving this message intermittently but frequently once I was driving the car even though I started the car without problems and did not receive the message before being underway. This problem was coincident with this upgrade, occurred with both key fobs and I never had it for the previous 7 years. It must be the upgrade, right? We replaced the key battery and Tesla service center ran all its tests and they showed normal. They also said that they have installed thousands of upgrades and have not had this as a reported issue. A mobil service technician ran several resets, also to no avail.

I stumbled on something that might help if you are encountering this problem. Lacking a right, back pocket in my sweat pants I have been keeping my wallet (with cards) and the key fob inside my right front pocket with the key fob outside the wallet, i.e. between the wallet and the center console. The slightest direct touch on the key fob causes the alert to go away. I've stopped keeping the key fob and my wallet in the same pocket and the problem hasn't yet reoccurred. Maybe it's some sort of interference between the credit cards and the key fob.

I'd be curious if others have had this problem and whether this solution works.

An RF security card (e.g., HID) used for many businesses, etc. will definitely cause this error if fob is next to it.

 

[CKiefer]

Thanks to you all for these comments. I'm assuming the cause has been identified and I just cancelled my third appointment with Tesla service.

 

[dannycamps]

I learned very early on that I needed to be careful about keeping my key fob in the same pocket as my iPhone.

This. I have confirmed that if I inadvertently put my key fob in the same pocket as my phone, my car will not recognize the key, not start when I press the pedal (key not detected), etc... The minute I take my phone out of my pocket, it works perfectly without issue. I can reproduce this 100% of the time. It's more of an annoyance than anything else.

 

[Ron Burgundy]

I get this issue weekly if not more - very frustrating.
Sometimes it happens before I can get the car going!
Scenario:
I will either have the key in my hand and eventually placed in the center console, or in my right front pocket by itself (no phone, RFID Cards or anything.
I have replaced the battery - no change.

I cannot determine why it happens, but it is frustrating.

 

[maximizese]

I've been getting the "key fob battery low" message ever since I did the MCU2 upgrade. Coincidentally, I had Tesla Service replace a faulty key fob. So now I have 3 fobs (one brand new), all 3 work and yet all 3 gives the low battery warning on the IC. I'll leave a message on the app to see if they can fix it remotely.

 

[Wol747]

Touching the key fob makes your body extend the range like an antenna. I used to hold my key fob up to my chin when unlocking other cars I own to increase the range. It works. My 2020 had issues like this whenever I was charging my Samsung phone in the Tesla wireless charger. Tech support said the phone was causing interference with the key fob receiver in the center console near the phone charger. Removing the phone from the charger solved this issue, and it doesn't cause any issues when I am sitting in the car to get the warning while it is charging.

Several years ago a TV programme had a piece showing this range extending method (Top Gear?)
I thought it just HAD to be an April fool type joke, but it turned out to be true!
Walk away from your garage and find the point where the remote consistently doesn't trigger the door, walk ten yards further and push the remote button while holding the remote against your head and 9 times out of 10 it triggers the door. Whether this works with all frequencies I don't know.

 

[KalJoMoS]

Maybe this discussion can help, it might need to be restarted, like described there…

 

[TDW911]

We’re getting the same issue with our 2018 Model S. it’s quite annoying and we need to press the key fob to get it to recognise the key again.
I’m intrigued by the comments above about interference from iPhones. We have the Tesla Wireless phone charger installed and there’s nearly always an iPhone in it so thinking maybe this is the issue.

 

[DerbyDave]

Tesla specifically asked me if I had a Samsung phone I was charging, so it must be worse. My phone is Samsung. Knowing what the issue is makes it not as urgent. A fix would be more difficult than a code upgrade. I am just living with it.

 

[solardudesf]

We’re getting the same issue with our 2018 Model S. it’s quite annoying and we need to press the key fob to get it to recognise the key again.
I’m intrigued by the comments above about interference from iPhones. We have the Tesla Wireless phone charger installed and there’s nearly always an iPhone in it so thinking maybe this is the issue.

Not sure if you have the same issue. I did not notice initially, but after taking my car in for service, they disabled passive entry on my car. This required me to press the key fob. I re-enabled it once I noticed and all was good again.