Case IH 2885 – Transmission Control Unit (TCU), Chassis Control Module (CCM / CCM2), or Universal Control Module (UCM): Park brake engage commanded, but park brake pressure is not below engaged threshold within expected time

The system commanded the brake to engage, but the park brake pressure switch or sensor did not detect the hydraulic pressure dropping below the required engagement threshold within the expected timeframe. This means either the hydraulic pressure is physically failing to vent (due to a stuck solenoid valve or blocked return line), or the pressure sensor/switch has failed and is falsely reporting high pressure to the controller.

• Steiger T4B
• Magnum tractors
• Steiger/Quadtrac tractors
• Axial-Flow combines (e.g., AFX8010, 7230-9230 series)

1. 1

   Verify physical brake state to determine if the machine is physically locking up (brake engaging) or if it rolls freely when the park brake is commanded on.

2. 2

   Inspect the wiring harness from the chassis main harness to the park brake pressure switch/sensor for chafing, corrosion, or open/short circuits.

3. 3

   Tee a manual hydraulic pressure gauge into the park brake release circuit (often located on the right side of the transmission or on the control pressure manifold) and observe if the actual hydraulic pressure drops when the brake is commanded on.

4. 4

   Perform a sensor plausibility check: if the manual gauge shows the pressure is dropping correctly, the park brake pressure switch/sensor is likely faulty. If the pressure is not dropping, the issue is hydraulic (likely a stuck park brake solenoid valve).

1. 1

   Safely park the machine on level ground and chock the wheels or tracks to prevent unintended movement, as you will be working on the braking system.

   Safely park the machine on level ground and chock the wheels or tracks to prevent unintended movement, as you will be working on the braking system.

2. 2

   Relieve all hydraulic pressure from the system before servicing.

   Relieve all hydraulic pressure from the system before servicing.

3. 3

   Locate the park brake pressure switch/sensor and the park brake solenoid valve.

   Typically located on the transmission control valve block or the primary hydraulic power system manifold.

4. 4

   Disconnect the electrical harness from the suspect component.

   Disconnect the electrical harness from the suspect component.

5. 5

   If replacing the sensor/switch: Unthread the faulty park brake pressure switch from the manifold.

   Install the new switch and torque to OEM specifications.

6. 6

   If replacing the solenoid: Remove the retaining nut and slide the coil off the valve cartridge.

   Unthread the cartridge from the manifold, inspect the O-rings, and install the new solenoid valve assembly.

7. 7

   Reconnect the electrical harnesses.

   Reconnect the electrical harnesses.

8. 8

   Start the machine, cycle the park brake switch several times, and verify that the fault code clears.

   Verify that the fault code clears and the park brake indicator functions correctly on the display.