Case IH 2028 (517966.13) - DEC – Transmission Control Unit (TCU): Clutch B not calibrated

The transmission controller has detected that a specific transmission clutch (Clutch A or Clutch B) lacks a valid calibration value. This results in poor clutch performance or the transmission being completely disabled by the controller for safety.

• VESTRUM CVX
• Case IH MXM series (MXM120 to MXM190)
• Case IH Puma
• Case IH Maxxum
• Case IH Magnum

1. 1

   Verify transmission oil temperature is between 10°C and 105°C (calibration will abort if too cold or too hot)

2. 2

   Verify engine RPM is stable (calibration will fail if RPM is too low or too high)

3. 3

   Ensure operator controls are set correctly: shuttle lever in neutral, main/range shift levers in neutral, clutch pedal fully released, and parking brake applied

4. 4

   Check for accompanying solenoid circuit electrical faults (e.g., codes 2022/2041 or 2023/2038/2039) which indicate an electrical issue rather than just a missing calibration

1. 1

   Prepare the Tractor

   Park on level ground in an unobstructed area. Engage the handbrake, switch off all electrical switches and the A/C. Set the shuttle control lever to neutral, lower the hydraulic lift arms, and put safety wedges under the wheels.

2. 2

   Run the Auto-Calibration

   Access the tractor's 'H' menu (diagnostic mode) via the instrument cluster to initiate the transmission clutch calibration procedure.

3. 3

   Observe Calibration Results

   If the calibration completes successfully (Code CF), clear the fault codes using the H8 (memory clear) mode. The tractor is ready for use. If the calibration fails or aborts, proceed to the next step.

4. 4

   Inspect the PWM Valve

   Locate the PWM (Pulse Width Modulation) solenoid valve for the affected clutch on the transmission control valve block. Remove the PWM valve, clean it thoroughly to remove any debris or sticking contaminants, and reinstall it.

5. 5

   Retest and Pressure Test

   Attempt the calibration again. If it still fails, perform a hydraulic pressure test on the clutch circuit to check for internal mechanical leaks.

6. 6

   Electrical Testing

   If the valve does not respond, use a multimeter to check the wiring harness from the solenoid back to the processor. The solenoid resistance should typically be approximately 6-8 ohms at 20°C. Repair the harness or replace the solenoid if it fails this test.