Case IH 2661 – ZTC: Range clutch BG is shorted to power

The control module is detecting positive voltage (B+) on the clutch solenoid's ground or control circuit when it should not be present. This typically happens if a wire in the harness has chafed and is touching a 12V power source, or if the solenoid coil has failed internally and shorted.

• Steiger T4B
• Case IH Steiger AFS Connect (CVT models)
• Case IH CVX / Optum CVXDrive series

1. 1

   Visually inspect the transmission wiring harness connecting the ZTC controller to the transmission solenoids. Look for pinched wires, melted insulation, or chafing that could expose the clutch control wire to a 12V power wire.

2. 2

   Disconnect the harness at the ZTC module and at the transmission housing. Inspect the pins for corrosion, moisture, or bent terminals that could bridge two circuits.

3. 3

   Using a multimeter, test the resistance (Ohms) of the Range Clutch BG solenoid coil. Compare it to the OEM spec (usually around 5–15 ohms for transmission solenoids). If it reads out of limits or shows continuity to the power supply, the solenoid is internally shorted.

4. 4

   With the solenoid unplugged, turn the key ON and measure the voltage at the harness connector. If 12V is present on the control wire, the short to power is in the wiring harness, not the solenoid.

1. 1

   Disconnect the tractor's battery to prevent electrical spikes.

   Disconnect the tractor's battery to prevent electrical spikes.

2. 2

   If the diagnostic tests isolate the short to the wiring harness, locate the damaged section. Splice and solder the damaged wires, sealing them with dual-wall heat shrink, or replace the affected transmission harness section.

   If the diagnostic tests isolate the short to the wiring harness, locate the damaged section. Splice and solder the damaged wires, sealing them with dual-wall heat shrink, or replace the affected transmission harness section.

3. 3

   If the diagnostic tests prove the solenoid is faulty, drain the transmission fluid (if required to access the valve body).

   If the diagnostic tests prove the solenoid is faulty, drain the transmission fluid (if required to access the valve body).

4. 4

   Remove the transmission valve body cover.

   Remove the transmission valve body cover.

5. 5

   Remove the retaining bolt/clip for the Range Clutch BG solenoid and extract the solenoid.

   Remove the retaining bolt/clip for the Range Clutch BG solenoid and extract the solenoid.

6. 6

   Install the new solenoid, lubricate the O-rings with clean hydraulic/transmission fluid, and torque the retaining bolt to OEM spec.

   Install the new solenoid, lubricate the O-rings with clean hydraulic/transmission fluid, and torque the retaining bolt to OEM spec.

7. 7

   Reassemble the valve body cover, refill the transmission fluid, and clear the fault codes via the tractor's diagnostic display.

   Reassemble the valve body cover, refill the transmission fluid, and clear the fault codes via the tractor's diagnostic display.

8. 8

   Perform a transmission clutch calibration (often required after replacing a CVT clutch solenoid).

   Perform a transmission clutch calibration (often required after replacing a CVT clutch solenoid).