Case IH 11121 – Remote Hydraulics Controller (AUX67, AUX89, or Armrest Controller): 2nd remote TIMER potentiometer is failed low.

The electronic controller is receiving a signal voltage from the 2nd remote valve's timer control potentiometer that is below the acceptable minimum threshold (typically near 0 volts). This condition usually points to a short to ground in the wiring harness, a disconnected plug, or an internal failure of the potentiometer itself located in the armrest console.

• STX Steiger
• Case IH Steiger / STX Series (STX275, STX280, STX330, STX380, STX430, STX480, STX530, 435, 535, Quadtrac)
• Case IH Magnum Series (MX Magnum, TG Series, 235-340 Series 4)

1. 1

   Inspect the timer control knob for the 2nd remote valve for physical damage or sticking.

2. 2

   Remove the armrest console cover and check the potentiometer connector for backed-out pins, corrosion, or broken wires (a severed signal wire or short to ground).

3. 3

   Verify the 5V reference voltage and ground at the potentiometer connector using a multimeter. Back-probe the signal wire while turning the timer knob; if voltage stays flat at 0V, the potentiometer is internally shorted or broken.

4. 4

   Swap the connector with the 1st remote timer potentiometer. If the fault code changes to the 1st remote (code 11111), the potentiometer is faulty. If code 11121 persists, the issue is in the wiring harness leading to the AUX controller.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Access the Armrest

   Remove the retaining screws (typically Hex Socket Head M4x20 or Slotted Pan Head #8-32) securing the upper housing of the right-hand armrest console.

3. 3

   Remove the Knob

   Carefully pull off the remote valve timer control button/knob from the top of the console.

4. 4

   Extract the Potentiometer

   Disconnect the wiring harness plug from the faulty potentiometer. Remove the mounting nut/plate securing the potentiometer to the secondary control panel.

5. 5

   Install the New Part

   Insert the new potentiometer, secure the mounting hardware, and press the timer control knob back onto the shaft.

6. 6

   Reassemble and Calibrate

   Reconnect the wiring harness, reinstall the armrest console cover, and reconnect the battery.

7. 7

   Clear Codes

   Use the tractor's AFS Pro display or an Electronic Service Tool to clear the AUX67/AUX89 fault codes and perform an armrest controller calibration if required by the service manual.