Case IH 734-13 - DEC – Transmission Control Unit (TCU) or Vehicle Control Unit (VCU): Transmission Range Clutch C1 Solenoid - Out of Calibration

The electronic control system has detected that the proportional solenoid valve controlling the C1 transmission clutch pack has lost its calibration parameters, or a required calibration routine has not been successfully completed.

• MAGNUM AFS Connect
• Case IH Steiger series
• Case IH Magnum / MX series
• Case IH Puma, Maxxum, and MXU series
• Case IH Farmall series

1. 1

   Verify that the transmission hydraulic fluid is at the correct level and is in good condition.

2. 2

   Ensure the transmission fluid is at normal operating temperature, as cold oil can prevent successful calibration.

3. 3

   Check the battery voltage, as extremely low voltage can cause the TCU to lose memory or fail to actuate the solenoid.

4. 4

   Inspect the wiring harness and connector at the C1 clutch solenoid for corrosion, damage, or loose pins.

1. 1

   Warm Up the Machine

   Start the tractor and operate it until the transmission hydraulic fluid reaches the normal operating temperature required for calibration.

2. 2

   Attempt Calibration

   Enter the tractor's calibration menu via the in-cab display monitor or connect the CNH Electronic Service Tool (EST) laptop.

3. 3

   Run Clutch Calibration

   Select the Transmission Calibration -> Clutch Calibration routine. Follow the on-screen prompts (this typically requires the parking brake to be engaged, the engine set to a specific RPM, and the system will automatically cycle the clutches).

4. 4

   Evaluate Results

   If the calibration completes successfully, clear the fault code and test drive the tractor. If the calibration fails specifically on the C1 clutch, proceed to step 5.

5. 5

   Inspect/Replace Solenoid

   If the wiring to the C1 solenoid is intact but it refuses to calibrate, the proportional solenoid valve is likely sticking or has failed internally. Relieve hydraulic pressure, remove the C1 clutch solenoid from the transmission control valve block, and replace it with a new OEM solenoid.

6. 6

   Recalibrate

   After replacing the solenoid, you must perform the transmission clutch calibration procedure again so the TCU can learn the fill times and pressure curves of the new valve.