Rather than checking the datastream I would check the sensor's resistance to make sure it's working as expected.

If the sensor is good, then next you need to check two things.

1. You saw the SES light is on, but you didn't say what actual code was being thrown. This is very important. Please check to see exactly what code is being set.
2. Especially if the SES code has nothing to do with the coolant temp sensor, I would suspect your ADX is using an incorrect translation for the coolant temp sensor.

I have zero experience with $8B so I cannot offer specific advice. But always, always start with the basics.