Case IH 2640 – ZTC: Range clutch K2 is open circuit

Electrical failure in the circuit responsible for actuating the K2 range clutch inside the transmission. The controller has detected infinite resistance (an open circuit), meaning electrical current cannot flow to the K2 clutch solenoid valve. This is typically caused by a broken wire, a disconnected or corroded wiring harness connector, or a completely failed (burned out) solenoid coil.

• Steiger T4B
• Case IH Puma CVX / CVXDrive series
• Case IH Maxxum CVX / CVXDrive series
• Case IH Optum CVXDrive series
• Case IH Farmall U Pro series

1. 1

   Visually inspect the wiring harness leading to the K2 clutch solenoid on the transmission valve block for chafing, rodent damage, or breaks.

2. 2

   Disconnect the plug at the K2 solenoid and check for pushed-out pins, water ingress, or corrosion. Clean the contacts with electrical contact cleaner.

3. 3

   Measure the resistance across the pins of the K2 solenoid using a digital multimeter (expected 10 to 30 ohms). If it reads OL (Open Loop), the solenoid coil has failed internally.

4. 4

   Measure the continuity of the wiring harness from the solenoid connector back to the ZTC module pins to isolate a broken wire if the solenoid tests good.

1. 1

   Preparation

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

2. 2

   Clean the Area

   Thoroughly clean the exterior of the transmission valve block around the K2 solenoid to prevent dirt from entering the hydraulic circuit.

3. 3

   Remove the Solenoid

   Disconnect the electrical connector. Remove the retaining bolts or snap-ring securing the K2 solenoid to the valve block.

4. 4

   Extraction

   Pull the solenoid straight out. Have a catch pan ready, as a small amount of transmission fluid will drain out.

5. 5

   Installation

   Lubricate the O-rings on the new solenoid with clean transmission fluid. Carefully insert the new solenoid into the valve block and torque the retaining bolts to the OEM specification.

6. 6

   Reconnection

   Reconnect the electrical harness until it clicks securely. Reconnect the battery.

7. 7

   Fluid Check

   Check the transmission fluid level and top off if necessary.

8. 8

   Calibration

   Connect a diagnostic tool (such as the Case IH Electronic Service Tool) to clear the inactive 2640 fault code. Crucial step: You must perform a transmission clutch fill calibration procedure so the ZTC can learn the engagement characteristics of the new K2 solenoid.