Case IH U128 – CCM (Central Control Module): Transmission oil temperature is above 55°C

This fault code indicates that the transmission fluid temperature has exceeded the safe operating threshold of 55°C (131°F) programmed for certain transmission configurations. (Note: On some heavier CVT models like the Puma CVX, this same U128 code designation is used when the temperature exceeds 105°C / 221°F). This condition can be caused by heavy load, degraded oil, restricted filters, or a faulty transmission oil temperature sensor giving a false reading.

• Farmall 105C
• Farmall 105U
• Farmall 115U Efficient Power Tractor
• Farmall 75C
• Puma 170 CVX
• Puma 185 CVX
• Puma 200 CVX
• Puma 215 CVX
• Puma 230 CVX
• Maxxum Series
• MX100
• MX110
• MX120
• MX135
• TM115-TM165

1. 1

   Check Fluid Levels and Condition: Verify that the transmission oil is at the correct level and not burnt or heavily degraded.

2. 2

   Sensor Verification: Test the transmission oil temperature sensor for accurate resistance/voltage scaling to rule out a false high-temperature reading.

3. 3

   Transmission Valve Ramp Test: Use the onboard diagnostic H-menu to test the transmission solenoids/valves. Depress the clutch pedal and use the shuttle lever to cycle through the valves available for testing. With the shuttle lever in forwards and the clutch pedal fully released, press and hold the transmission upshift button to perform the ramp test for the selected valve.

1. 1

   Warm the Oil

   Operate the tractor until the transmission oil reaches a temperature greater than 60°C (140°F) to suspend contaminants.

2. 2

   Drain and Replace

   Stop the engine and immediately drain the transmission oil.

3. 3

   Filter Replacement

   Remove and replace all transmission and hydraulic oil filters.

4. 4

   Sensor Replacement

   If faulty, unplug the wiring harness from the transmission oil temperature sensor, unthread the old sensor from the transmission housing, and install the new sensor.

5. 5

   Refill Fluid

   Add the correct transmission oil (e.g., Case IH Akcela Hy-Tran or Akcela TSM BIO oil) to the specified level.

6. 6

   Clear Fault Codes

   Turn the ignition key switch ON. Access the diagnostic menu. Navigate to the HC menu (Use HC to erase stored error codes without erasing calibration information. Warning: The H8 menu will clear all calibration values alongside the fault codes). The lower central display will show 'EECL' or 'F CL'. Depress and hold the 'm' (dimming) button to confirm the clearing of the memory.