Case IH 6029 – TCU or TCM: 2WD Solenoid - LSD short to GND

The low side of the 2WD solenoid circuit is permanently connected to ground. This indicates that the wiring harness between the controller and the solenoid has rubbed through and is touching the chassis ground, the solenoid coil has internally shorted, or the Low Side Driver inside the controller has failed and is 'stuck on'.

• MAXXUM T4E
• Magnum series (e.g., 200, 220, 235-340 Tier 4B CVT models)
• Puma series (e.g., 165, 180, 195, 210, 225 CVX)
• Farmall series (e.g., 95U, 105U, 115U Pro)

1. 1

   Visually inspect the wiring harness for physical damage, rubbing, or pinched wires between the TCU/TCM and the 2WD solenoid.

2. 2

   Inspect the 2WD solenoid connector (e.g., X-285) and the main controller harness for loose connections, moisture, corrosion, or bent pins.

3. 3

   Disconnect the 2WD solenoid and measure the resistance of the solenoid coil to verify it has not failed internally.

4. 4

   With the solenoid disconnected, check the ground circuit wire for continuity to the chassis ground to isolate a shorted harness.

5. 5

   If the wiring and solenoid test good, check the TCU for an internal failure (Low Side Driver watchdog test failed or stuck on).

1. 1

   Turn off the machine and disconnect the battery to prevent further module damage.

2. 2

   Locate the 2WD Solenoid on the transmission/MFD valve block.

3. 3

   Disconnect the 2-way connector (BAS AMP Superseal 1.5) from the solenoid.

4. 4

   If the harness is shorted to ground, trace the wire back to the TCU, locate the chafe point, repair the wire, and wrap it in protective loom.

5. 5

   If the solenoid coil is internally shorted, remove the retaining nut/bolt, slide the old solenoid coil off the valve stem, and install the replacement solenoid.

6. 6

   If the wiring and solenoid are intact but the fault persists, the TCU must be replaced or sent out for repair due to a burnt-out internal Low Side Driver.

7. 7

   Reconnect the battery, clear the fault codes, and test the 2WD/4WD engagement to verify the repair.