Ok so here's the scoop...

Check the resistance of the solenoids. If the resistance is above 50 ohms:
Inspect the front differential solenoid jumper harness connector, repair/replace as necessary. If OK, replace the shorted front differential solenoid in accordance with the service information. (same for the rear)

If solenoid isn't shorted, there's a whole bunch of tests to do on the control side of the harness... but a lot of them require activating the circuit with a scan tool and checking for output with a test light. There's also instructions for checking for shorts... but it depends whether the DTC is for a high or low voltage circuit fault; and typing up all 40 pages is, well, a lot of work! So see what resistance you're getting and go from there.

If you have a way of pulling the code that would help a lot with the troubleshooting.