Explanation: The controller has detected a short circuit on a master valve (MV1 = master valve 1, MV2 = master valve 2).
If the load placed on the master valve circuit exceeds the skip current setting in the advanced menu (default for this setting is 1.5 amps or 1500 milliamps) it will create this fault message. Each time the controller runs the master valve it will test the output, if it exceeds the skip current setting it will not run and all zones using the master valve will not irrigate. If the output returns to normal, the fault will automatically be cleared.
Resolution: Typically, short circuits are caused by an issue with the valve solenoid which should be tested first. Inspection of the wiring from the controller to the solenoid may also be required. You can test the valve circuit using a the controller's built in milliamp meter or an electrical multimeter on the ohms (Ω) setting. [See here for a tutorial on testing ohms] A normal reading is approximately 200-350 mA and 20-60 ohms. A circuit of less than 12 ohms can result in a blown fuse. A reading of less than 20 ohms means the wiring to the valve has an issue. You should check the wiring and splices in the valve box for breaks in wire insulation.
If your multimeter shows a reading higher than 20 ohms but you are getting a short message, your solenoid will likely need to be replaced.
You can also change the settings to alter the amount of load placed on the circuit before a fault is created. To do this turn the dial to the advanced menu position and use the up and down buttons to scroll until the screen shows "SKIP CUR" and press the next button. Use the up and down buttons to set the desired value, ranging from 1.0 amps (1,000 milliamps) to 2.5 amps (2,500 milliamps). Please note that the controller is equipped with a 1.0 amp slow blow fuse and drawing more than 1 amp for an extended period of time will blow the fuse.
Once the issue has been resolved, you should manually clear the fault and run the program to make sure the fault has been fixed.