Case IH 737-06 - DEC – DEC: Transmission C4 clutch solenoid electrical circuit fault current above normal

The controller has detected an excessive current draw on the circuit for the C4 clutch solenoid. This condition is almost always caused by a short circuit to ground in the wiring harness or an internal short within the solenoid coil itself.

• MAGNUM AFS Connect
• Maxxum series (5120, 5130, 5140, 5150)
• Magnum series

1. 1

   Inspect the transmission wiring harness routing down to the transmission control valve block for rubbed, pinched, or melted wires shorting to the tractor chassis.

2. 2

   Disconnect the C4 clutch solenoid connector and check for water ingress, corrosion, or damaged pins that could bridge the circuit.

3. 3

   With the solenoid disconnected, turn the key ON and use a multimeter to check the power supply wire for a short to ground.

4. 4

   Measure the resistance across the pins of the C4 clutch solenoid. A reading of 0 ohms (or significantly below OEM specification) confirms the solenoid coil is internally shorted.

5. 5

   If the wiring tests fine, swap the C4 clutch solenoid with an adjacent clutch solenoid (e.g., C3). If the fault code changes to reflect the new position, the solenoid is definitively the culprit.

1. 1

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

2. 2

   Locate the transmission control valve block on the side of the transmission housing.

3. 3

   Identify the C4 clutch solenoid using the transmission valve block diagram.

4. 4

   Thoroughly clean the area around the solenoid to prevent dirt from entering the transmission hydraulic system.

5. 5

   Disconnect the electrical connector from the C4 solenoid.

   If the wiring harness was found to be shorted during diagnostics, cut out the damaged section and splice in a new terminal connector.

6. 6

   Remove the retaining bolt or snap ring securing the C4 solenoid to the valve block.

7. 7

   Pull the faulty solenoid straight out.

8. 8

   Lubricate the O-rings on the new replacement solenoid with clean transmission fluid.

   e.g., Ambra Mastertran Ultraction

9. 9

   Install the new solenoid into the valve block and secure it with the retaining hardware.

10. 10

    Reconnect the electrical connector.

11. 11

    Turn the key ON and use the tractor's instrument display or an electronic service tool to clear the inactive fault codes.

12. 12

    Warm up the tractor and perform a transmission clutch calibration procedure.

    This ensures the DEC learns the engagement characteristics of the new C4 solenoid.