New Holland 15580 – TCU or VCM: Pressure in the power steering auxiliary system not created

The control system has detected a lack of hydraulic pressure within the auxiliary circuit of the power steering system. This indicates that the components responsible for generating, regulating, or transmitting hydraulic fluid to the steering mechanism are not functioning correctly, which will result in a loss of power-assisted steering and negatively affect steering performance and control.

• T6.120
• T6.140
• T6.160
• T7.170
• T7.210
• T7.270
• T6030
• T6050
• T6070
• TS100A
• TS115A
• LM Series
• TJ330
• 8870
• 9682
• TM125
• TM140

1. 1

   Check hydraulic fluid level and quality in the reservoir (milky fluid indicates water contamination, dark/burnt fluid indicates overheating)

2. 2

   Inspect all steering system components (hoses, fittings, cylinders, pump) for external hydraulic leaks

3. 3

   Check hydraulic filters and suction screens for clogs that could restrict fluid flow

4. 4

   Inspect for air in the system causing spongy hydraulics; purge air if necessary

5. 5

   Listen for unusual whining or cavitating noises from the hydraulic pump

1. 1

   Test hydraulic pump output

   Use a pressure gauge to measure the hydraulic pump's output and compare it to service manual specifications. Rebuild or replace the pump if pressure is low.

2. 2

   Inspect priority valve

   Check the priority valve to ensure it is not sticking or malfunctioning, which can cut off flow to the steering system. Clean, free up, or replace the valve as needed.

3. 3

   Check steering control valve

   Test the operation of the steering orbital/hand pump with a pressure gauge to ensure it is correctly directing fluid to the steering cylinders.

4. 4

   Inspect steering cylinders

   Perform a drift test to check for internal leaks, and inspect for external leaks. Replace worn seals using a cylinder seal kit if necessary.

5. 5

   Test pressure switches and sensors

   Test the steering circuit pressure sensor and its wiring for continuity and correct operation. Replace the sensor if it is faulty and triggering the code erroneously.