Case IH U71 – TCU: Calibration Attempted With Enable Switch OFF

This fault code is triggered when the system receives a command to begin a transmission calibration procedure, but the required safety or enable switch is not activated. It can also occur if the enable switch was already in the ON position when the tractor was started, as the system logic requires the switch to be cycled to prevent accidental calibrations.

• Puma/Mid Range Magnum
• Puma
• Mid Range Magnum
• Puma 130
• Puma 140
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225 CVX
• Magnum 7100
• Magnum 7200
• MX Series
• TG Series

1. 1

   Verify that the enable switch is actually flipped to the ON position before starting the calibration.

2. 2

   Check if the enable switch was left in the ON position before the tractor was keyed on, as the system will lock out calibration until the switch is cycled.

3. 3

   Inspect the wiring harness and the connector at the back of the enable switch for loose pins, broken wires, or corrosion.

4. 4

   Use a multimeter to test the enable switch for proper continuity when toggled to the ON position to rule out internal switch failure.

1. 1

   Cycle the switch

   If the switch was ON at startup, turn the enable switch OFF, and then turn it back ON to reset the system logic.

2. 2

   Repeat calibration

   Attempt the transmission calibration procedure again.

3. 3

   Inspect and repair wiring

   If the U71 code persists, access the rear of the enable switch on the console. Disconnect the harness and check for voltage and ground. Repair any damaged wires or secure loose connections.

4. 4

   Replace the switch

   If the wiring is intact but the switch fails a continuity test, remove the faulty enable switch from the console and install a replacement.

5. 5

   Final calibration

   With the new switch installed or the system properly reset, turn the enable switch ON and complete the transmission calibration.