Case IH 128 – TMF or AUX: Aux 2nd Lower solenoid failed open or short circuit

This indicates an electrical fault in the circuit that controls the lowering function of the 2nd auxiliary (remote) hydraulic valve. The controller has detected that the circuit is either broken (open circuit) or shorted to ground/power, preventing the solenoid from operating correctly.

• Magnum
• Case IH MX Magnum Series
• Case IH TG Series
• Case IH STX Steiger Series

1. 1

   Visually inspect the wiring harness and connector leading to the 2nd remote valve lower solenoid at the rear of the tractor for chafed wires, broken connections, or severe corrosion.

2. 2

   Perform a resistance test across the solenoid coil pins with a multimeter (an infinite reading indicates an internal open circuit, while 0 ohms indicates an internal short).

3. 3

   Check the harness side of the connector for a short to ground or a short to 12V.

4. 4

   Perform a swap test by exchanging the 2nd Lower solenoid coil with the 2nd Raise solenoid coil (or a coil from the 1st/3rd remote). If the fault code changes to match the new position, the coil is faulty. If it remains 128, the issue is in the wiring harness or controller.

1. 1

   Park and prepare tractor

   Park the tractor on a level surface, lower all implements, turn off the engine, and disconnect the battery to prevent electrical spikes.

2. 2

   Relieve hydraulic pressure

   Relieve any residual hydraulic pressure in the remote valves by cycling the remote levers/switches in the cab.

3. 3

   Locate solenoid

   Locate the auxiliary remote valve stack at the rear of the tractor. Identify the 2nd remote valve block and locate the "Lower" solenoid.

4. 4

   Disconnect harness

   Disconnect the electrical wiring harness plug from the faulty solenoid.

5. 5

   Remove retaining nut

   Remove the retaining nut or fastener at the end of the valve cartridge that secures the solenoid coil in place.

6. 6

   Remove old coil

   Slide the old solenoid coil off the valve stem. (Note: You typically do not need to open the hydraulic system or remove the valve cartridge to replace just the coil).

7. 7

   Install new coil

   Slide the new solenoid coil onto the stem and secure it with the retaining nut. Do not overtighten, as this can crack the plastic coil housing.

8. 8

   Reconnect harness

   Reconnect the electrical harness plug, ensuring the weather seal is intact.

9. 9

   Reconnect battery and clear codes

   Reconnect the battery, start the tractor, and clear the stored fault codes.

10. 10

    Verify operation

    Actuate the 2nd remote valve from the cab to verify proper operation and ensure the code does not return.