Komatsu 700K Crawler Dozer VCU 116.0 and VCU 116.4: Troubleshooting and Solutions

[MikePhua]

The Komatsu 700K crawler dozer is a robust machine widely used in construction and mining operations. However, like any complex machinery, it can encounter issues that affect its performance. One such issue is the appearance of error codes VCU 116.0 and VCU 116.4, which are related to the parking brake system. This article delves into the causes of these error codes, their implications, and the steps to resolve them.
Understanding the VCU 116.0 and VCU 116.4 Error Codes
The VCU (Vehicle Control Unit) 116.0 error code indicates a high brake pressure when the parking brake is engaged. This abnormal pressure reading can lead to the machine entering a derate mode, limiting its power and performance. The VCU 116.4 error code, on the other hand, often appears when the sensor detecting the brake pressure is disconnected or malfunctioning, leading to a voltage reading below normal.
Diagnosing the Issue
To accurately diagnose the problem, it's essential to perform a series of checks:

1. Measure Brake Pressure: Using a pressure gauge, measure the brake pressure when the parking brake is engaged. A healthy system should show a pressure of approximately 428 psi. If the pressure is significantly higher, it indicates an issue.
   
2. Inspect the Brake Pressure Sensor: The brake pressure sensor is located just above the left drive motor on a small block with a solenoid. If the sensor is disconnected or faulty, it can lead to erroneous readings and trigger the error codes.
   
3. Check for Pressure When Parking Brake is Engaged: There should be no pressure to the parking brake when it is engaged. If pressure is present, it suggests a malfunction in the park brake release solenoid.
   

Common Causes and Solutions

1. Faulty Brake Pressure Sensor: If the sensor is providing incorrect readings, it can trigger the error codes. Replacing the faulty sensor with a new one can resolve the issue.
   
2. Stuck Park Brake Release Solenoid: If the solenoid is stuck, it may allow pressure to reach the parking brake even when it is engaged. Cleaning or replacing the solenoid can rectify this problem.
   
3. Wiring Issues: Damaged or corroded wiring can lead to incorrect voltage readings. Inspecting and repairing any wiring issues can help eliminate the error codes.
   

Preventive Measures
To prevent the recurrence of these issues:

• Regularly inspect the brake system components for wear and tear.
  
• Ensure that the wiring connections are clean and secure.
  
• Perform routine maintenance as per the manufacturer's guidelines.
  

Conclusion
The appearance of VCU 116.0 and VCU 116.4 error codes in the Komatsu 700K crawler dozer is indicative of issues within the parking brake system. By systematically diagnosing the problem and addressing the underlying causes, operators can restore the machine's full functionality and prevent future occurrences. Regular maintenance and timely interventions are key to ensuring the longevity and optimal performance of the dozer.