Case IH 55091 – NAV Controller / Steering Controller: Front Steer movement with no command

Occurs when the sum of the sampled electrical current passing through the electro-hydraulic steering solenoids is larger than the expected minimum for manual mode operation (exceeds 0.12 Amps for front-steer), despite the auto-steer system not sending a command.

• STX Steiger
• Puma
• Magnum
• Steiger
• Quadtrac
• STX Series
• STX-275
• T9 series
• MXM series
• TM series

1. 1

   Clear the controller fault via the AFS Pro / IntelliView display to rule out an intermittent software or voltage spike

2. 2

   Inspect the cable harness from the NAV controller to the steering valve coils for chafing, pinched wires, or corrosion

3. 3

   Test the electro-hydraulic solenoids on the steering valve to verify if they draw current above 0.12 Amps in manual mode

4. 4

   Inspect the steering position sensor and actuator linkage for physical damage, looseness, or debris

5. 5

   Check the RFComm Status in the Advanced NAV Computer screen to verify sensor communication

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent electrical shorts while working on the steering valve harness.

2. 2

   Repair Wiring

   If the diagnostic inspection revealed damaged wiring between the NAV controller and the steering valve, repair or replace the affected harness section.

3. 3

   Replace Solenoids/Valve

   If the wiring is intact but the steering valve solenoids are shorted internally or drawing excessive current without a command, replace the faulty steering valve coils. If the coils cannot be serviced separately or the valve is failing internally, replace the entire steering control valve assembly.

4. 4

   Reassemble and Power Up

   Reconnect all electrical connectors and restore battery power.

5. 5

   Clear Codes

   Turn on the display, navigate to the FAULTS screen, and clear the 55091 fault code.

6. 6

   Recalibrate Steering

   Perform a vehicle steering calibration via the display. The steering should be calibrated to be as aggressive as it can be without causing vibration or chatter. Once properly calibrated, test the auto-steer system in the field to ensure the cross-track error is minimized and the fault does not return.