Case IH 6028 – Transmission Control Unit (TCU) / Generic Electronic Module (GEM): Transmission Temperature Sensor / 2WD Solenoid - Generic Error

The system detects that the transmission fluid temperature is either too high (>110°C), too low (<110°C), or that the temperature sensor input circuit (specifically pin 43) is open-circuited. Alternatively, it indicates an open circuit, short to ground, or short to battery in the 2-Wheel Drive transfer case solenoid circuit.

• MAXXUM T4E
• 580N
• 580SN
• 590SN
• TN series
• Maxxum series

1. 1

   For Code 6028 (Transmission Temp): Verify actual transmission temperature. If too high (>110°C), allow to cool and inspect cooling system for blockages or low fluid.

2. 2

   For Code 6028: If temperature is too low, warm up the transmission to see if the code clears.

3. 3

   For Code 6028: Check the wiring harness between the transmission temperature sensor and the ECU for an open circuit (specifically at pin 43).

4. 4

   For 2WD Solenoid Error: Read and record all stored codes and freeze-frame data with a scan tool.

5. 5

   For 2WD Solenoid Error: Visually inspect connectors, pins, and wiring at the transfer case and control module for corrosion, damage, or water intrusion.

6. 6

   For 2WD Solenoid Error: Backprobe the solenoid connector and measure key-on and commanded voltages and ground.

7. 7

   For 2WD Solenoid Error: Measure the solenoid coil resistance and compare it to OEM specifications to determine if the coil is open or shorted.

1. 1

   Locate sensor

   For Code 6028 (Transmission Temp Sensor): Locate the transmission oil temperature sensor on the transmission housing.

2. 2

   Inspect connector

   For Code 6028: Disconnect the electrical connector and inspect for corrosion.

3. 3

   Remove sensor

   For Code 6028: If the wiring is intact but the sensor reads out of specification (or is open-circuited), unthread the old sensor.

4. 4

   Install sensor

   For Code 6028: Install the new transmission temperature sensor and torque to OEM specifications.

5. 5

   Test machine

   For Code 6028: Reconnect the wiring harness, clear the fault codes, and test the machine under load.

6. 6

   Locate valve block

   For 2WD Solenoid Error: Locate the 2WD/4WD solenoid valve block on the transmission/transfer case.

7. 7

   Disconnect connector

   For 2WD Solenoid Error: Disconnect the 2WD solenoid electrical connector.

8. 8

   Remove hardware

   For 2WD Solenoid Error: Remove the retaining hardware securing the solenoid to the valve body.

9. 9

   Remove solenoid

   For 2WD Solenoid Error: Remove the faulty solenoid and inspect the hydraulic ports for debris.

10. 10

    Install solenoid

    For 2WD Solenoid Error: Install the new 2WD solenoid (e.g., HI-LO clutch engagement solenoid) and secure the retaining hardware.

11. 11

    Verify engagement

    For 2WD Solenoid Error: Reconnect the electrical connector, clear the codes, and verify proper 2WD/4WD engagement.