Case IH 50 – Transmission Controller (TRANS): Park Brake is stuck off by the electrical power being stuck on when commanded off

The parking brake is spring-applied and hydraulically released. Code 50 triggers when the controller commands the parking brake to engage (by cutting power to the solenoid), but the system detects that electrical power is still present or the valve remains stuck open. This leaves the parking brake disengaged (stuck off), creating a safety hazard.

• MX Magnum
• STX Steiger
• Magnum Series
• Steiger & Quadtrac Series
• Puma Series
• MX Series
• TG Series

1. 1

   Verify if the tractor's battery recently died or was disconnected (a dead battery causes the Electronic Park Lock to lose calibration).

2. 2

   With the key switch ON and the tractor not running, disconnect the park brake pressure switch connector and measure continuity across the switch pins (must be closed and show less than 2 ohms of resistance).

3. 3

   Check if there is still hydraulic pressure at the park brake circuit when the brake is commanded ON (power commanded off), which indicates a mechanically stuck open valve.

4. 4

   Inspect the wiring harness leading to the park brake solenoid for a short to power condition.

1. 1

   Re-initialize the Electronic Park Lock (EPL)

   Sit in the seat and hold down both brake pedals.

2. 2

   Re-initialize the Electronic Park Lock (EPL)

   Release the hand brake.

3. 3

   Re-initialize the Electronic Park Lock (EPL)

   Turn the ignition key to the RUN position (do not start).

4. 4

   Re-initialize the Electronic Park Lock (EPL)

   Place the shift lever in the NEUTRAL position.

5. 5

   Re-initialize the Electronic Park Lock (EPL)

   Press the Neutral button on the shifter handle. The brake should release and the code may clear.

6. 6

   Replace the Park Brake Solenoid

   If initialization fails, locate the park brake solenoid valve. On many Magnum models, it is located on the valve bank behind the top step/cab filter area (behind the cab pressurizer fan). On Steiger models, it is located on the transmission valve body.

7. 7

   Replace the Park Brake Solenoid

   Clean the area around the valve to prevent debris from entering the hydraulic system.

8. 8

   Replace the Park Brake Solenoid

   Disconnect the electrical connector from the solenoid.

9. 9

   Replace the Park Brake Solenoid

   Remove the retaining nut/bolts and carefully pull the faulty solenoid valve cartridge out of the manifold.

10. 10

    Replace the Park Brake Solenoid

    Lubricate the O-rings on the new updated solenoid valve with clean hydraulic fluid.

11. 11

    Replace the Park Brake Solenoid

    Install the new solenoid valve and tighten to OEM torque specifications.

12. 12

    Replace the Park Brake Solenoid

    Reconnect the electrical harness.

13. 13

    Replace the Park Brake Solenoid

    Clear the fault codes using the instrumentation panel or a dealer service tool.

14. 14

    Replace the Park Brake Solenoid

    Start the tractor and test the parking brake engagement/disengagement to ensure the code does not return.