Case IH 122 – Transmission Controller (TRANS): ICU model range error

The CAN model number broadcasted by the Instrument Cluster Unit (ICU) is not recognized or supported by the transmission control system.

• STX Steiger
• STX Steiger Series 4WD
• STX 280
• STX 325
• STX 375
• STX 440
• STX 500

1. 1

   Verify repair history to see if the Instrument Cluster Unit (ICU) was recently replaced, swapped from another machine, or updated

2. 2

   Check programmed configuration by accessing the CONFIG ICU options on the display to see what tractor model the ICU is currently broadcasting

3. 3

   Verify part numbers by cross-referencing the part number printed on the back of the installed ICU with the tractor's specific Product Identification Number (PIN) to ensure correct hardware

1. 1

   Attempt Reconfiguration

   If the ICU is a programmable replacement, enter the configuration menu and ensure the correct tractor model and transmission type (e.g., Manual Shift vs. Power Shift) are selected.

2. 2

   Remove the Incorrect ICU

   If the hardware is fundamentally incompatible, power down the tractor and disconnect the battery. Remove the right-hand cab ROPS post trim to access the ICU.

3. 3

   Disconnect Harnesses

   Carefully unplug the main harness connectors (typically CN1, CN2, and CN3) from the back of the cluster.

4. 4

   Install the Correct ICU

   Mount the new, correct Instrument Cluster Unit and reconnect the wiring harnesses. (Note: If upgrading an older STX tractor from an original ICU to an ICU2, you must install the OEM adapter module and jumper harnesses).

5. 5

   Calibrate and Configure

   Power up the tractor. The transmission controller will read the new model number. You may need to navigate the CONFIG ICU menu to set the fuel tank size, tire size, and perform a radar calibration so the system stores the new baseline.

6. 6

   Clear Codes

   Cycle the key and verify that the TRANS fault code has cleared.