It gives no fault codes. It will go to COO and just sit there.
I am not sure what COO means.
If a thermistor is bad wouldn't it still run for at least a minute? I've checked ohms at the board and at them. The one on the exhaust housing is 7k ohms.
It may monitor the thermistor resistances all the time.
The resistance does look low according to the chart.
The two outside red wires. I get 110 from the top red to ground.
This will be for the heater voltage.
You were probably looking at @M which is connected directly to L2 voltage.