It sounds like you're on the right track and must know that the error means the thermistor is out of range. It's possible that the thermistor came faulty, but not likely. If you have a multimeter you can test and see for sure what the problem is. Here are the steps.
1. Unplug dryer or disconnect power.
2. Access the machine control panel electronics.
3. Remove the P14 connector on the main control board, then measure the resistance between P14-3 (red-white wire) and P14-6 (red-white wire) at the connector.
5. If 5–15 kΩ are measured, replace the machine control electronics. If the resistance is greater than 20 kΩ, replace the exhaust thermistor.
Now my guess is that the control board is bad since you already replace the thermistor already but if you wanted to test first you can definitely do that.
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