Case IH FAC – Transmission Control Unit (TCU): Clutch C Solenoid Open Circuit Or Short To Ground

The controller has detected a critical electrical fault in the circuit responsible for operating the Clutch C solenoid valve. The circuit is either physically broken (open circuit) or the wiring/internal coil has shorted directly to the ground. When this code is active, the transmission controller disables the affected clutch pack to prevent mechanical damage.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190

1. 1

   Verify that the battery voltage is sufficient, as the transmission controller will fail to operate the clutch solenoids properly if the system voltage drops too low.

2. 2

   Trace the wiring harness from the Transmission Controller to the Clutch C solenoid on the transmission valve body. Look for chafed wires, breaks, or melted insulation that could cause a short to ground.

3. 3

   Disconnect the plug at the Clutch C solenoid. Inspect for moisture, dirt, or corroded pins.

4. 4

   Use a multimeter to measure the resistance across the pins of the Clutch C solenoid. If the reading shows an open circuit (infinite resistance) or a dead short (zero resistance), the solenoid itself has failed internally and must be replaced.

1. 1

   Prep the Machine

   Park the tractor on a level surface, lower all implements to the ground, place all shift levers in neutral, and block the wheels.

2. 2

   Depressurize and Disconnect

   Relieve hydraulic pressure in the system and disconnect the tractor's battery to prevent electrical shorts during the repair.

3. 3

   Locate the Solenoid

   Locate the transmission control valve body (PMV block) where the clutch solenoids are mounted.

4. 4

   Remove the Faulty Solenoid

   Disconnect the electrical connector from the Clutch C solenoid. Unbolt the solenoid from the valve body.

5. 5

   Clean and Install

   Clean the mounting surface on the valve body to ensure no debris enters the hydraulic system. Install the new solenoid, ensuring the O-rings/seals are properly seated, and bolt it down.

6. 6

   Reconnect

   Reconnect the electrical harness and the battery.

7. 7

   Transmission Calibration

   After replacing a transmission clutch solenoid, you must recalibrate the transmission clutches. Start the engine and set the engine speed to 1200 RPM (±100). Press and hold the High and Low range buttons until 'CAL' appears in the transmission display, then release. Follow the on-screen prompts to allow the TCU to learn the engagement pressures of the new solenoid.