I just put on a new 180 degree thermostat and both CLT sensors. I got a code for CLT signal voltage too high. Could the lower thermostat cause this?

Hmm, thats odd. I would pull out the multimeter & check some voltages on the CTS wiring, I believe it is a 5V sensor.

I wouldn't see a lower degree thermostat causing this, unless the ECU is used to seeing different temps after a specific time of running/warm up period. Maybe its possible the new thermostat is opening too soon for the ECU to recognize.

Or just simply reset it & see if the code comes back at a specific range in the operating temp.

Jeff.

Ok test across the connector not the sensor? Ill try that. When sitting it heats up to about 188 to 190s. After driving then sitting for a like 8 minutes it hit 206 then fan turned on and came back down. I was trying to test the fan haha.

Doubt it. I ran a 160* stat when I was bone stock living in Phoenix back in the day.

Check the resistance values of the sensor (big one, the small one is only for the gauge and has nothing to do with the code). Additionally, check the connector and any related wiring for a possible short.