Case IH 2085 – CCU or TCU: Fuse low error / Synchro 4 solenoid open circuit

Depending on the system generating the code, 2085 indicates either a low voltage supply error (typically a blown fuse) logged by the CCU, or a break in the electrical circuit for the Synchro 4 solenoid logged by the TCU.

• Farmall
• Steiger
• Magnum
• Maxxum
• Puma

1. 1

   For Fuse Low Error: Ensure the key switch is in the 'OFF' position.

2. 2

   For Fuse Low Error: Locate the main fuse panel (often located at the base of the right-hand console or in the cab fuse box).

3. 3

   For Fuse Low Error: Inspect the fuses related to the CCU permanent battery power supply and transmission power supply.

4. 4

   For Fuse Low Error: Check the battery voltage to ensure the system is receiving adequate power.

5. 5

   For Fuse Low Error: If a fuse is blown, inspect the associated wiring harness for shorts to ground before replacing it, as a dead short will cause the new fuse to blow immediately.

6. 6

   For Synchro 4 Solenoid Open Circuit: Inspect the transmission wiring harness for damaged wires, loose connectors, or bent pins between the TCU and the Synchro 4 solenoid.

7. 7

   For Synchro 4 Solenoid Open Circuit: Disconnect the Synchro 4 solenoid and use a multimeter to test the resistance of the solenoid coil. If it reads out of specification or infinite (open), the solenoid has failed internally.

8. 8

   For Synchro 4 Solenoid Open Circuit: Test for continuity on the wiring harness from the TCU connector to the solenoid connector to rule out a broken wire.

1. 1

   Turn the ignition key switch to the 'OFF' position.

   To resolve the Fuse Low Error.

2. 2

   Access the main fuse panel and remove the blown fuse.

   To resolve the Fuse Low Error.

3. 3

   Replace the blown fuse with a new fuse of the exact same amperage rating (e.g., 10A or 15A depending on the specific CCU circuit).

   Do not replace a blown fuse with another of a different rating than specified.

4. 4

   Turn the key ON and clear the fault codes.

   If the fuse blows again, you must trace the circuit to locate and repair the short to ground.

5. 5

   Disconnect the tractor's battery.

   To resolve the Synchro 4 Solenoid Open Circuit.

6. 6

   Disconnect the wiring harness connector at the Synchro 4 solenoid on the transmission block.

7. 7

   Remove the retaining hardware and extract the faulty solenoid.

   Perform this if the wiring is intact but the solenoid failed the resistance test.

8. 8

   Install the replacement Synchro 4 solenoid and tighten to OEM torque specifications.

9. 9

   Reconnect the wiring harness, ensuring the connector is fully seated, locked, and free of moisture/debris.

10. 10

    Reconnect the battery, power on the tractor, and use a diagnostic tool to clear the code.

    A transmission calibration (clutch/synchro calibration) may be required after replacing transmission solenoids.