Recently I had my Check Engine Light came on in my Jeep. I pulled the codes and got a 22 which translates to the ECT is out of voltage range. The Coolant Temperature sensor is located in the thermostat housing on my Jeep. I first tried cleaning the contacts as they light come on intermittently. That did not work so I ended up replacing the sensor.
First,I removed the wire. Then, Loosened the radiator cap to make sure all the pressure was gone. I also prepped the new sensor with some sealant on the threads. I used a 19mm wrench to unscrew the old sensor. I quickly swapped in the new sensor with minimal coolant loss. I then topped up the system with coolant to replace the little I lost during the swap. I reconnected the wire and called it done.
No more check engine light this morning.