Case IH PCF – Transmission Control Module (TCM) / Power Control Unit (PCU) / Electronic Management Unit (EMU): 1 CAN Chip, Shorted To High Source

The Controller Area Network (CAN) communication chip inside the control module has detected a short circuit to a high voltage source (typically battery voltage) on the CAN bus lines. This disrupts communication between the tractor's electronic systems.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190

1. 1

   Inspect the CAN bus wiring harness connecting to the transmission controller for chafed wires, melted insulation, or bare wires shorting directly to a 12V power source.

2. 2

   Disconnect the transmission controller and inspect the pins for corrosion, moisture, or bent pins that could be bridging a power circuit to the CAN lines.

3. 3

   Use the tractor's built-in diagnostic system (H-Menu) to run the H8 routine to clear the non-volatile memory (EEPROM) and reset stored fault codes.

4. 4

   Attempt a transmission calibration to see if the TCF code returns. If the code immediately returns and the wiring is intact, the CAN chip inside the controller is fried.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical damage during the swap.

2. 2

   Locate the Module

   Locate the Transmission Control Module / EMU, which is typically mounted in the operator's platform/cab area (behind the right-hand console or dashboard).

3. 3

   Remove the Faulty Module

   Carefully unplug the multi-pin wiring harnesses from the module. Remove the mounting hardware (usually M5 x 10mm bolts) and extract the faulty controller.

4. 4

   Install the New Module

   Mount the replacement Transmission Control Module and secure it with the hardware. Reconnect the wiring harnesses securely.

5. 5

   Restore Power

   Reconnect the battery.

6. 6

   Perform Transmission Calibration

   Start the engine and set the engine speed to 1200 ERPM. Press and hold the High and Low range buttons until 'CAL' appears on the transmission display. Follow the on-screen prompts (the display will show numbers increasing as it calibrates the clutches) until 'END' is displayed, signifying completion.