Case IH U148 – Transmission Control Module (TCM) or Central Control Module (CCM): Range lever not in the high range position

This fault code indicates that the transmission control system expects the range lever to be in the high range position, but the corresponding sensor/switch is not detecting it.

• Maxxum
• Case IH Farmall Series
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 115U
• T5 110 S
• Boomer series

1. 1

   Verify the operator is fully pushing the range lever into the high range detent

2. 2

   Inspect the range lever linkage from the cab down to the transmission cover for excessive play, worn ball-and-socket joints, or loose roll pins

3. 3

   Test the High Range Switch on the transmission housing for continuity to ensure it closes properly when the lever is in the high position

4. 4

   Use the tractor's on-board 'H' diagnostic routines (e.g., H5 Switch Diagnostics) to verify if the module is receiving the signal from the High Range Switch

5. 5

   If linkage and switch are functioning properly, inspect for damaged internal mechanicals (e.g., bent shift forks or worn range collars)

1. 1

   Adjust the Linkage

   If the linkage is sloppy or out of adjustment, loosen the jam nuts on the linkage rod. Adjust the rod length so that when the lever is in the high range position, the transmission detent is fully engaged and the high range switch is depressed. Tighten the jam nuts.

2. 2

   Replace Worn Linkage Components

   If adjustment maxes out due to wear, replace the worn pivot arms, roll pins, or ball joints in the shift linkage.

3. 3

   Replace the High Range Switch

   If the switch fails a continuity test or the on-board diagnostic test, disconnect the wiring harness, unthread the old switch from the transmission housing, and install a new one.

4. 4

   Internal Transmission Repair

   If the tractor physically jumps out of gear or will not shift into high range despite good linkage, the transmission cover must be removed to replace the range collar, shift pivot arm, or synchronizers.

5. 5

   Recalibration

   After repairs, you may need to run a transmission or PTO calibration (e.g., accessing the H1 or R1 calibration menus) to ensure the CCM relearns the clutch quick-fill times and switch positions.