Case IH t2C – Transmission / EDC (Electronic Draft Control) / PCU (Powertrain Control Unit): Battery Voltage, Data Valid But Above Normal Range

This is an overvoltage condition where the control module is receiving a voltage reading that exceeds the safe operating threshold for the tractor's electrical system (typically anything over 15 volts while the engine is running).

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

1. 1

   Battery Voltage Test (Engine Off): Use a multimeter to check the resting voltage at the battery terminals. It should read approximately 12.4V to 12.6V.

2. 2

   Alternator Output Test (Engine Running): Start the tractor and measure the voltage at the battery and at the back of the alternator (main charge post). Normal charging voltage should be between 13.5V and 14.5V. If the reading exceeds 15V, the alternator's internal voltage regulator has failed and is overcharging the system.

3. 3

   Wiring and Ground Inspection: Check the main battery cables, chassis grounds, and the wiring harness leading to the transmission controller. Look for shorts to a higher voltage source or loose/corroded grounds that could cause voltage spikes or erratic readings.

1. 1

   Disconnect Power

   Disconnect the negative battery cable before performing any electrical repairs.

2. 2

   Replace the Alternator/Regulator

   If the diagnostic checks confirm the alternator is overcharging, remove the serpentine belt and unbolt the faulty alternator. Install the replacement alternator and re-tension the belt.

3. 3

   Clean Connections

   Clean the battery terminals, cable ends, and the main chassis ground with a wire brush to ensure a solid connection. Reconnect the battery.

4. 4

   Verify Voltage

   Start the tractor and verify with a multimeter that the charging voltage is now within the normal 13.5V–14.5V range.

5. 5

   Clear Codes and Recalibrate

   Clear the t2C fault code from the system. Because this code affects the transmission controller, you may need to perform a transmission/EDC calibration (using the High and Low range buttons to enter "CAL" mode) to ensure shift quality and clutch featherability are restored.