It’s possible for a DCM, Data Communications Module, to fail and you may not know it. At least in my case, as always, your mileage may vary.

The SOS illuminated button is a visual indicator of SOS function and or DCM status. As explained in the manual (this is not a direct quote from the manual) when you start your car, the SOS button runs a self-test (of what all is being tested, I don’t know) the light cycles from red to green.

In my case, I lost destination assist and remote start, my reason for my service visit to the dealer. Turns out the car had a failed DCM and the SOS button appeared to be function properly through its self-test. However, the tech determined, while the SOS appeared to be able to work it did not place the “call” to Lexus Enform Services.

My warranty has lapsed and I’m responsible for the cost of the repairs and parts needed.

Please refer to your manual(s) for information relevant to the items discussed here and your car.

 

If your car is 2019 you might want to post this under RX4 section

 

Yes, my current car is a 2019. However, I wanted to join a conversation regarding Data Communication Module(s), which are common to most cars after model year 2018 and many Lexus prior to that date.

Perhaps I will start a conversation where it belongs in a generalized thread.