Hi nwalker280,
Welcome to the forum.
Have you inspected and cleaned inside your cell?
The salt sensor can just get caked with too much calcium, of which a normal cleaning won't necessarily take care of.
If it's dirty and you catch the scale build up early, you can just hose it off with a high pressure wand. Always try to clean with water 1st. Remember to get up by where the cord enters the cell. This is where the salt sensor is.
If you can't get it clean using just water, then you have to do an acid soak.
Use 4 parts water to 1 part acid. Add the acid to the water, never the other way around.
If the cell is exceptionally scaled you can use a 3:1 solution, but never stronger than 2:1.
Pull the cell once it stops bubbling, do not let it sit in the acid solution longer than necessary. When it's done, pull it out then rinse it off.
Here is more detail on cleaning it.
TURBO CELL CLEANING INSTRUCTIONS
Also, check your instant salt reading. It should be within about 500/600ppm of what your salt test kit, or test strips show. The more it drifts, the higher the indication that the cell is going bad.
See this link for how to perform the above checks.
High Salt Reading - Troubleshooting
I have never seen anything on replacing just the sensor inside the cell.
But that doesn't mean it can/can't be done.
Also, can you post a full set of test results for your pool? As well as what method you are using to test the salt yourself, aside from Leslies. What brand of test strips are you using?