Codes P0660 and C0205, 4lo blinking and check engine light on?

So, these are two different problems please start a new thread for the p0660. The C0205 code will stop the 4wd from engaging. I would scan the ABS system to see which wheel sensor is not working. Also, get under the truck to see if any of the sensor wires have been ripped out of their connector, which happens when road debris gets kicked up while driving.

P0660: This code typically relates to a problem in the Intake Manifold Tuning Valve Control Circuit/Open, on bank 1.

C0205: This is a chassis code and often relates to the vehicle's Anti-lock Brake System (ABS) or the wheel speed sensor circuit.

Here is a guide to help you with the scan and the location of the wheel speed sensors so you can check it out:

https://www.2carpros.com/articles/anti-lock-system-testing-and-repair-abs

Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.