Case IH 520203-31 - VCM – VCM / UCM / PVED-CLS: Vehicle speed triggered EH-steering shut-off (Safety function 3) - Condition exists

The vehicle's speed has exceeded the maximum calibrated safety threshold (specified by parameter P3253) for the electrohydraulic (EH) steering system to operate. When this threshold is breached, the controller automatically disables the auto-guidance/auxiliary steering functionality and forces the steering system into a safe on-road state to prevent loss of control.

• MAGNUM AFS Connect
• MX Magnum

1. 1

   Verify actual vehicle speed to confirm the operator is not driving too fast while auto-guidance is engaged (speed exceeds platform limit).

2. 2

   Check the vehicle speed sensor and its wiring for erratic, shorted, or failing signals sending erroneously high speed data via the CAN bus.

3. 3

   Inspect the roading switch to ensure it is not stuck closed or reading outside of a valid voltage range.

4. 4

   Verify the PVED-CLS controller configuration parameters using a diagnostic service tool (Case IH EST or Danfoss PLUS+1), specifically checking if the speed threshold parameter (P3253) is corrupted or set incorrectly.

1. 1

   Operator Correction

   If the fault was triggered by operator error, reduce the vehicle speed below the platform limit to restore auto-guidance functionality.

2. 2

   Sensor Replacement

   If diagnostics point to a faulty vehicle speed sensor sending implausible data, replace the speed sensor and clear the codes.

3. 3

   Clean area

   If the PVED-CLS controller requires replacement, clean the area around the EH steering valve and hydraulic reservoir to prevent contamination.

4. 4

   Relieve pressure

   Relieve all hydraulic system pressure.

5. 5

   Disconnect harnesses

   Disconnect the electrical harnesses (CAN bus and power connections) from the PVED-CLS controller.

6. 6

   Disconnect hoses

   Mark the orientation of the hydraulic fittings, then disconnect the hoses from the EH steering valve.

7. 7

   Remove valve assembly

   Remove the mounting bracket hardware and remove the EH steering valve assembly.

8. 8

   Install new assembly

   Install the new EH steering valve / PVED-CLS controller assembly.

9. 9

   Reconnect hoses

   Reconnect the hydraulic hoses using new, lubricated O-rings.

10. 10

    Reconnect harnesses

    Reconnect the electrical harnesses.

11. 11

    Refill reservoir

    Refill the hydraulic reservoir with the specified hydraulic fluid and operate the machine to inspect for leaks.

12. 12

    Calibrate system

    Calibrate the steering position sensor and the Electrohydraulic (EH) valve spool using the diagnostic service tool, as the new controller must be taught the specific valve parameters.