Case IH 123 – TMF (Tractor Multifunction) Controller or AUX (Remote Hydraulics) Controller: Aux 1st Lower Coil solenoid shorted to 12 volts.

This code indicates that when the lever for the first auxiliary remote section is in the Neutral position, the controller is sensing voltage on the circuit. Under normal operation, the controller should provide no voltage to the solenoid when in Neutral. If voltage is detected, the system flags a short to a 12-volt power source.

• Magnum
• Case IH Magnum Series
• MX Magnum
• Case IH TG Series
• Case IH Puma Series
• Case IH Maxxum Series

1. 1

   Verify system voltage at cavity 1 and 12 of the controller connector (e.g., connector C053) is within 9.8 - 14.5 volts. If it is outside this range, check the battery and the alternator regulator.

2. 2

   Check the controller ground at cavity 2 and 11 at the same connector for a solid connection to a clean chassis ground.

3. 3

   Inspect the wiring harness running from the controller to the 1st Aux Lower Coil solenoid for chafed wires or melted insulation that could be causing the circuit to short directly to a 12V source.

4. 4

   Clear the fault codes, shut down the tractor, and restart it to see if the fault immediately returns while the lever is in neutral (indicating a hard fault).

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the negative battery cable to prevent electrical damage during testing.

2. 2

   Locate the Valve Block

   Locate the electro-hydraulic remote valve stack at the rear of the tractor. Identify the 1st auxiliary remote valve and its lower coil solenoid.

3. 3

   Test the Solenoid

   Disconnect the electrical connector at the 1st Aux Lower Coil solenoid. Using a multimeter, check for continuity to a 12V power source on the harness side. If voltage is present when it shouldn't be, trace the harness back to the controller to repair the short.

4. 4

   Check Coil Resistance

   Measure the resistance across the solenoid coil pins. If the coil is internally shorted, remove the retaining nut, slide the old solenoid coil off the valve cartridge, and replace it with a new one.

5. 5

   Controller Replacement (If Necessary)

   If the wiring harness is intact and the solenoid tests fine, the Remote Hydraulics Controller has likely suffered an internal failure (stuck driver). The controller will need to be replaced.

6. 6

   Reassembly and Calibration

   Reconnect all harnesses and the battery. Start the tractor, clear the fault codes, and test the 1st remote valve for proper extend/retract operation.