2005 ford escape with a overdrive light flashing and the code P0715 came up.How to fix it?

More than likely this sensor or other issue with this system is causing the poorly running condition.

Basically, this is used for shift points so if it is not operating properly then we need to address this and go from there.

Here is a guide that will help with this testing:

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Please see the testing below and that will get us to the issue that we need to resolve.

Let us know what questions you have. Thanks