Case IH 518585-05 - UCM – UCM: Brake assisted steering left solenoid current low

This code indicates that the electrical current flowing to the left brake-assisted steering (BAS) solenoid is below the minimum operational threshold. This typically points to an open circuit, high resistance in the wiring harness, a disconnected plug, or a failed solenoid coil on the left side of the brake-assist valve block.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400

1. 1

   Inspect the wiring harness leading to the brake-assisted steering valve block (typically located near the rear axle/differential) for pinched wires, chafing, or debris damage.

2. 2

   Disconnect the left BAS solenoid connector and check for water ingress, bent pins, or corrosion.

3. 3

   Measure the resistance across the pins of the left brake-assisted steering solenoid (a healthy 12V DC PWM solenoid should measure approximately 7.3 Ohms).

4. 4

   Measure continuity from the solenoid connector back to the UCM to rule out a broken wire, and check for any shorts to ground.

5. 5

   Back-probe the connector and command a left-hand turn with the brake-assist system active (via the HMC II headland management system) to verify the UCM is sending the correct PWM voltage signal to the solenoid.

1. 1

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

   Ensure the machine is safely parked before beginning work.

2. 2

   Disconnect the negative battery cable.

   Prevents electrical shorts during the repair.

3. 3

   Locate the PTO / Differential / Brake-Assisted Steering valve block assembly.

   This is located at the rear of the tractor.

4. 4

   Disconnect the electrical harness from the faulty left BAS solenoid.

   Carefully remove the connector from the solenoid.

5. 5

   Remove the solenoid retaining cover/nut.

   This secures the solenoid to the valve body.

6. 6

   Slide the faulty electric actuator solenoid off the valve stem.

   Note: If the valve cartridge itself is leaking or sticking, the hydraulic system may need to be depressurized to replace the entire cartridge, but for a 'current low' electrical code, usually only the coil needs replacing.

7. 7

   Slide the new PWM solenoid onto the valve stem.

   Secure it with the retaining cover.

8. 8

   Reconnect the electrical harness.

   Ensure the weather seal clicks firmly into place.

9. 9

   Reconnect the battery.

   Restore power to the tractor.

10. 10

    Clear the inactive 518585-05 fault code.

    Use the Case IH Electronic Service Tool (EST) or the AFS Pro 1200 display.

11. 11

    Field test the tractor.

    Engage the brake-assisted steering system and perform a tight left-hand turn to confirm the inside brake engages and the code does not return.