Case IH U22 – Transmission Module (TCU): ERPM is above 1350, reduce throttle

Triggers when the Engine RPM (ERPM) exceeds 1350 RPM during a procedure that requires lower engine speeds, such as transmission clutch calibration or quick-fill time adjustments.

• Puma/Mid Range Magnum
• Farmall
• Maxxum
• MXM
• Puma Series 140, 165, 180, 195, 210, 225 CVX
• Farmall Series 40, 45, 50, 115U
• Steiger Series
• Maxxum Series MXM 120, 130, 140, 155, 175, 190
• MX / TG Series

1. 1

   Verify that the operator has not simply left the hand or foot throttle set too high

2. 2

   Use the H9 diagnostic menu in the transmission module to see if the engine speed is actually being detected by the TCU

3. 3

   Verify that the instrument cluster is fully powered, as it acts as a gateway/display for these signals

4. 4

   Check for a broken CAN bus communication line between the engine, instrument cluster, and transmission module

1. 1

   Reduce Throttle

   Manually reduce the engine throttle so the RPM drops below 1350. If you are attempting a transmission calibration, ensure the engine is at the correct specified idle speed.

2. 2

   Verify RPM Signal

   If the engine is physically idling below 1350 RPM but the U22 code remains active, enter the H9 menu on the tractor's display to view the live engine speed data reaching the transmission module.

3. 3

   Restore Cluster Power

   If the H9 menu shows no RPM signal, check the fuses and relays powering the instrument cluster. Restore power if the cluster is dead.

4. 4

   Repair CAN Bus

   If the cluster is powered but the transmission module still cannot read the engine speed, use a multimeter to test the CAN bus wiring harness for continuity and shorts. Repair any broken CAN wires between the Engine ECU and the Transmission Module.