Case IH 734-06 - DEC – Transmission Control Unit (TCU) or Electronic Control Module (ECM): Transmission C1 clutch solenoid - Current above normal or grounded circuit

The controller has detected a short circuit to ground in the C1 clutch solenoid's electrical circuit. The current draw is exceeding the normal operating range, which typically causes the transmission controller to disable the affected gears or lockup clutch to prevent damage.

• MAGNUM AFS Connect
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• Magnum 7110
• Magnum 7120
• Magnum 7130
• Magnum 7140
• Magnum 8940
• Steiger 9270
• Steiger 9280
• Steiger STX500
• Maxxum 5120
• Maxxum 5130
• Maxxum 5140
• Maxxum 5150
• Maxxum 110
• Maxxum 115
• Maxxum 125
• Maxxum 140
• MXU110
• MXU135

1. 1

   Inspect the machine wiring harness between the transmission controller and the C1 clutch solenoid (Connector No. 31) for chafed wires, melted insulation, or pinched wires shorting to the chassis.

2. 2

   Disconnect the harness at the C1 clutch solenoid and inspect the pins for corrosion, moisture, or bent terminals.

3. 3

   Measure the resistance across the C1 clutch solenoid coil pins using a multimeter. Extremely low resistance or continuity to the solenoid housing indicates an internal short.

4. 4

   Perform a harness isolation test with the solenoid disconnected by checking for continuity between the harness power supply wire and ground. Continuity indicates a short in the wiring harness.

5. 5

   Perform a wiggle test on the transmission harness while monitoring with a diagnostic tool or multimeter to locate intermittent shorts.

1. 1

   Prepare machine for service

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and disconnect the battery.

2. 2

   Locate C1 clutch solenoid

   Locate the transmission control valve manifold (powershift valve block) on the side of the transmission housing. Identify the C1 clutch solenoid.

3. 3

   Disconnect solenoid

   Disconnect the electrical connector from the C1 clutch solenoid.

4. 4

   Repair harness (if applicable)

   If repairing the harness: Splice in a new terminal connector or repair the chafed wire using proper heat-shrink connectors.

5. 5

   Remove solenoid retaining hardware

   If replacing the solenoid: Remove the retaining nut or bolt holding the solenoid coil/cartridge in place.

6. 6

   Remove faulty solenoid

   Carefully pull the faulty solenoid cartridge out of the valve body.

7. 7

   Install new solenoid

   Lubricate the O-rings on the new solenoid with clean transmission fluid and insert it into the valve body.

8. 8

   Secure solenoid

   Tighten the retaining nut/bolt to the specified OEM torque.

9. 9

   Reconnect electrical and battery

   Reconnect the electrical connector and reconnect the battery.

10. 10

    Clear fault codes

    Clear the fault codes using the tractor's diagnostic display.

11. 11

    Perform calibration

    Perform a transmission clutch calibration (specifically for the C1 clutch) using the in-cab display or service tool, as the new solenoid will have slightly different flow characteristics than the old one.