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The link Biguggy gave you below helps explain the F70 error code, but that document fails to mention that this can also be caused by a short in the MCU (Motor Control Unit) or MCU to CCU (Central Control Unit) harness.
You did not give me the model number for the Duet you are working on. Some Duet washers have two User Interfaces (UI) others have one. The troubleshooting is a little different for both of those. In order to give you accurate and complete information on your washer I will need the model number. The model number should be located inside the loading door or on the back panel.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website;
Sears Home Services
Here is a link that you may use to view the parts list diagram or purchase any parts needed for your appliance;
Sears Parts Direct
If you would like specific help with your washer, please include the model number and more details in a reply to this post.