Hello all. My 600 had its keys stop working yesterday. Both sets have the same issue. It will start when I place the key to the start button so I am not totally in trouble. What are some likely candidates for this issue. I found a thread about something similar happening with a 2014 460 and it went to the dealer for several $1k in diagnostics and there wasn't a final answer. It could be the ECU, BCM, or the entry antenna according to that. Am I missing other options? I need to check the fuse box when my wife gets home later. I disconnected the battery overnight. Replaced the 12v battery completely. No changes. Thanks

 

It could be Radio-Frequency-Interference. Try moving your car to a different location. Be sure to leave your portable electronic devices behind. Have you recently added an electronic device such as a radar detector or power converter?

 

Did you try changing the battery in one of the fobs ?

 

Yes, I have tried several locations. No new electronics.

 

I have new batteries to put in later today. I can't imagine that will work though as both died the same say.

 

New batteries and no change. Could it be the oscillator or the key control module?

 

On the wireless remote key you should see a red LED flash when you press the LOCK or UNLOCK button. You don’t need to be in the presence of the car. Do you see the red LED flash?

 

Yes. It also flashes when tapping to start button.

I have attached Tech Stream and have no error codes that I can find.

 

Does the car respond to the LOCK and UNLOCK buttons on the wireless remote key when the car is within range? Thirty feet or less should be within range. It would be a good idea to check both wireless remote keys as we go.

 

Neither fob responds at all. The only thing they will do is the NFC communication with the start button allowing me to tap to start. Once started the dash flashes that the key is missing.

 

The fact that the red LED flashes on your key is a good indication that the key battery is good, and the key is probably good too.

Since the NFC feature seems to be working, that is a good sign that you have the right keys.

The touchless key feature can be disabled through the customization feature but that doesn't disable the remote LOCK and UNLOCK so that seems to be ruled out.

I have followed this forum closely for 18 years and have only seem a couple of reports of something like you are experiencing. Both seemsd to be RFI related. The cars seem to be exceptionally reliable as to the electronic key feature. Of course there is always the possibility of flood damage and rodent damage. Knowing the history of your car can help you assess those possibilities. Odds are the cause is something other than a component failure.

The information you have provided seems to point to RFI. But you have done the right things to rule that out somewhat. A GPS jammer could cause similar problems. Is your navigation system doing OK? A remote possibility but something that has to be considered is that a tracking device has been attached to your car.

I wish I could be more helpful. Thank you for sharing

 

Thank you for the info. I found the keyless module under the desk to the left of the brake pedal. I reseated the plugs and now it works. It COULD have been the brake pedal switch I replaced at the same time but that seems really unlikely. My guess is is that the plug was loose and somebody accidentally bumped the cables with their foot getting out.