CLAAS Id7624h / 7624h (405) – TR2 (Transmission Module 2): Pressure anomaly in the high-pressure braking system during initialization

The system detects that the pressure of the high-pressure brakes is between 78 bar and 98 bar, whereas the expected normal range at initialization is between 98 bar and 120 bar. The pressure value reported by the sensor is artificially higher (by approximately 2 to 4 bar) than the actual physical pressure in the hydraulic circuit. The brake indicator light on the dash will be blinking.

• Arion 400
• Arion 410
• Arion 430
• Arion 500
• Arion 510
• Arion 550
• Arion 600
• Arion 620
• Arion 640
• Arion 650
• Axion 800
• Axion 810
• Axion 850
• Axion 900
• Axion 920
• Axion 950
• Axion 960

1. 1

   Check the service brakes hydraulic circuit (valves, pipes, selector, conjunctor/disjunctor block) for physical leaks or damage

2. 2

   Check the high-pressure braking pressure sensor (B233 or B368) for measurement consistency (sensor drift is a primary suspect)

3. 3

   Test the high-pressure braking solenoid valve (Y329) to ensure it is opening correctly and receiving proper power

4. 4

   Check the wiring harnesses and connectors for the aforementioned components for continuity, proper power supply, and signal integrity. Also, verify the voltage delivered by the transformer (V24)

5. 5

   Inspect the rear service brake pressure accumulator (5016 or 5063) to ensure it is holding its nitrogen charge and not inflating too frequently

1. 1

   Depressurize the System

   Safely park the tractor, turn off the engine, and pump the brake pedals to relieve residual hydraulic pressure in the accumulators before opening any lines.

2. 2

   Inspect Wiring

   Using a multimeter, test the wiring harness from the TR2 module (A57-2 / A142) to the pressure sensor (B233/B368) and the solenoid valve (Y329). Repair any shorts, breaks, or corroded pins.

3. 3

   Test/Replace the Pressure Sensor

   If the wiring is intact, the fault is highly likely to be a drifted pressure sensor (B233/B368) reporting an inaccurate baseline pressure. Remove and replace the sensor.

4. 4

   Test/Replace the Solenoid Valve

   If the sensor is accurate, remove the Y329 solenoid valve. Check for sticking spools or blown O-rings. Replace the valve if it fails to actuate smoothly when 12V is applied.

5. 5

   Reinitialization

   After replacing the faulty component, restart the tractor. Depress the brake pedals to force the brake accumulators to inflate. The error code will clear automatically once the pressure in the rear brake circuit rises above the accumulator inflation start threshold during the reinflation phase (outside of the initialization phase).