Case IH 735-03 - DEC – Transmission Control Unit (TCU) or Electronic Control Module (ECM): Transmission C2 clutch solenoid electrical circuit fault voltage above normal

The control module has detected the voltage on the C2 clutch solenoid circuit is higher than the expected normal operating range, indicating a short to battery, internal coil failure, or control module failure.

• MAGNUM AFS Connect
• Steiger series
• MXM
• JXU
• JXC
• MXU series
• Magnum series
• Maxxum series
• Puma series

1. 1

   Verify the Code: Ensure that the diagnostic code 735-03 is currently active.

2. 2

   Check for Shorts to Battery: Disconnect the C2 clutch solenoid and probe the energize circuit of the machine harness to check for a short to the +battery circuit.

3. 3

   Measure Resistance: Measure the resistance of the C2 clutch solenoid coil to determine if it has shorted out internally.

4. 4

   Inspect the Harness: Visually inspect the transmission wiring harness and the C2 clutch solenoid connector for visible damage, corrosion, or pinched wires that could bridge the circuit to a power source.

1. 1

   Prep the Machine

   Power down the tractor, disconnect the battery, and relieve any residual hydraulic pressure in the transmission system.

2. 2

   Locate the Solenoid

   Locate the transmission control valve body where the C2 clutch solenoid is mounted (typically on the side of the transmission housing).

3. 3

   Disconnect

   Unplug the electrical connector from the C2 clutch solenoid. Clean the area around the valve to prevent debris from entering the transmission.

4. 4

   Wiring Repair (If Applicable)

   If your diagnostic tests indicated a wiring short to battery voltage, trace the harness back to the ECU and repair or replace the damaged section of the wiring harness.

5. 5

   Remove the Solenoid

   If the solenoid itself failed the resistance test, unbolt and remove the faulty C2 clutch solenoid from the valve body.

6. 6

   Install the New Part

   Install the new solenoid valve (or replacement coil) and torque to the manufacturer's specifications.

7. 7

   Reconnect

   Reconnect the electrical connector, ensuring the weather seal is intact and free of corrosion.

8. 8

   Test

   Reconnect the battery, turn on the ignition, and clear the inactive fault codes using a diagnostic tool. Start the tractor and test the transmission through its gears to ensure smooth shifting and verify that the 735-03 code does not return.