Case IH t1C – Transmission Control Module / EDC: Voltage monitoring, data incorrect

The controller is receiving an implausible or incorrect voltage signal, typically pointing to a wiring issue, a poor connection, or a fault within the monitoring module itself.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• MX210
• MX230
• MX255
• MX285

1. 1

   Turn the Power OFF and Keyswitch OFF. Disconnect the connectors at each end of the suspect circuit to prevent false multimeter readings.

2. 2

   Check the secondary controller (CFPS) connector C330 and the engine torque/RPM sensor connector C255. Ensure they are securely connected, not damaged, the pins are in the correct position, and the fit is tight.

3. 3

   Set your multimeter to measure resistance (ohms). Check for continuity, short to ground, short to 12 volts, and open circuits. (Resistance of no more than 3 to 4 ohms is continuous; high resistance indicates dirty/corroded terminals; 100K ohms indicates an open circuit).

4. 4

   Verify via the diagnostic menu if the engine speed has exceeded 3000 rev/min, which can trigger related data faults.

1. 1

   Wiring Repair

   Clean any corroded pins or replace damaged connector terminals on C330 or C255. Repair any open or shorted wires in the harness.

2. 2

   Verification

   Reconnect all harnesses and turn the key switch to the 'ON' position. If the error code clears, the tractor is functioning correctly and the issue was a poor connection.

3. 3

   Module Replacement

   If the wiring is perfectly intact and the voltage data remains incorrect, the Transmission Control Unit / Microprocessor has failed internally and must be replaced.

4. 4

   Mandatory Calibration

   If the microprocessor, a potentiometer, or a PWM solenoid valve is replaced, or if a mechanical transmission repair is performed, you must perform the Transmission/EDC Calibration Set Up Procedure: Place all shift levers in neutral and lower all equipment to the ground. Block the front and rear wheels. Press and hold the High and Low range buttons and start the engine. Release the buttons when 'CAL' appears in the transmission display. Set the engine speed to 1200 ERPM (± 100) and follow the on-screen prompts to calibrate the clutches and synchronizers.