What is Kobelco SK140LC-8 Fault Code 06564?

Fault Code 06564 on the Kobelco SK140LC-8 indicates a Main Pump Control Solenoid Valve malfunction, specifically a short circuit or open circuit in the electrical circuit controlling the hydraulic pump's displacement control system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects abnormal voltage or resistance values in the proportional solenoid valve that regulates the main pump's swash plate angle.

This fault is critical for the SK140LC-8 because the main pump control system directly governs hydraulic flow and pressure throughout the entire machine. When this circuit malfunctions, the excavator cannot properly modulate hydraulic power delivery to the boom, arm, bucket, and swing functions, severely compromising operational efficiency and cycle times.

Common Symptoms

• Reduced hydraulic power across all functions, with noticeably slow boom and arm movements
• Erratic or hunting hydraulic response where implement speeds fluctuate unpredictably during operation
• Warning lamp illumination on the instrument cluster, often accompanied by audible alarm tones
• Engine over-revving without corresponding increases in hydraulic performance due to pump displacement remaining at minimum angle
• Complete loss of hydraulic function in severe cases where the ECM enters protective derate mode

Potential Causes

The most common technical causes for Code 06564 on used SK140LC-8 excavators include:

• Solenoid valve coil failure due to internal winding breakdown from heat cycling and age-related deterioration
• Wiring harness damage at the harness routing point near the main pump, where vibration causes insulation wear and conductor exposure leading to short circuits
• Connector corrosion at the 4-pin pump control solenoid connector, particularly common in machines operating in coastal or high-humidity environments
• ECM internal driver circuit failure affecting the pulse-width modulation (PWM) output controlling solenoid current
• Contamination or mechanical binding of the solenoid valve spool preventing proper electrical response

How to Troubleshoot and Fix Code 06564

Step 1: Initial Electrical Verification Using a digital multimeter, disconnect the solenoid valve connector and measure coil resistance across the solenoid terminals. Kobelco specifications typically call for 8-12 ohms at 20°C. Values outside this range indicate solenoid replacement is necessary. Also check for continuity between each terminal and ground—any continuity indicates a short circuit.

Step 2: Harness and Connector Inspection On used excavators, carefully inspect the wiring harness routing from the ECM to the pump solenoid. Pay special attention to the section passing over the pump mounting area where harness flex occurs. Look for insulation chafing, exposed copper, or evidence of previous repairs. Clean all connector terminals with electrical contact cleaner and inspect for bent pins or green corrosion deposits.

Step 3: Dynamic Circuit Testing Reconnect the harness and use a breakout harness or backprobe the connector while monitoring voltage with the key on, engine off. The ECM should supply approximately 12V battery voltage. Start the engine and observe the PWM signal—it should vary between 0-12V as hydraulic demand changes. A constant voltage indicates ECM driver failure.

Step 4: Component Replacement and Verification If electrical tests confirm solenoid failure, replace the proportional control valve assembly with genuine Kobelco parts to ensure proper PWM frequency compatibility. After replacement, clear codes using Kobelco diagnostic software and perform a controlled function test under load to verify proper hydraulic response restoration.

Disclaimer: This guide provides general troubleshooting information. Always consult the Kobelco SK140LC-8 service manual for complete specifications and safety procedures. Complex hydraulic and electrical diagnostics should be performed by certified technicians with proper diagnostic equipment.