To determine if this is a possibility, the valve must first have a removable power element — not all of them do. Second, you need to determine if the reason for the TXV not controlling the refrigerant’s superheat value leaving the evaporator is the power element. A common failure of the power element is a loss of its fluid charge. The fluid charge within the power element applies the required pressure on the top of its diaphragm to move the valve’s port to a more open position. With the loss of this fluid, the valve may not be able to open enough to allow the correct amount of refrigerant to enter the evaporator. This will result in a higher-than-normal superheat value leaving the evaporator.  

There are other issues involving the TXV that can lead to a higher-than-normal superheat value leaving the evaporator, which is why it is important to make sure that the TXV is causing the issue. Then you will need to decide if the power element or something else within the TXV is the issue, such as a stuck push rod or clogged strainer.  

One possible test is to cut the pigtail of the sensing bulb. If no refrigerant or very little refrigerant comes out of the power element, it lost its charge. However, this is a one-time try; you will need to be ready to change out the entire valve if you find the power element has not lost its fluid charge. Also, I have seen some TXVs where the power element has lost its charge and the push rod was stuck, and we were forced to change out the entire valve anyway. So, it is always safest to change out the entire valve to ensure the problem is resolved — but the tradeoff is dealing with the tight location.   

Unfortunately, there is no clear-cut choice when dealing with this scenario. It is up to the technician to make the best decision at the time and be ready for Plan B if replacing the power element does not solve the problem. But when replacing the power element solves the issue, it does make for a much simpler and easier repair.