What is Doosan DX150LC-9C Fault Code E000105-06?

Fault Code E000105-06 indicates a "Main Control Valve Solenoid Valve 6 - Current Below Normal or Short Circuit to Ground" condition on the Doosan DX150LC-9C excavator. This diagnostic trouble code (DTC) is triggered when the Electronic Control Unit (ECU) detects abnormally low electrical current flowing through the main control valve's sixth solenoid, or when the circuit has developed a direct path to ground.

This code specifically affects the hydraulic pilot control system, which governs critical machine functions like boom, arm, or auxiliary hydraulic circuit operations. The solenoid valve acts as an electro-hydraulic interface, translating electrical signals from the ECU into precise hydraulic movements. When current drops below the manufacturer's threshold (typically due to circuit resistance or grounding issues), the hydraulic proportional control becomes compromised, directly impacting operational precision and productivity on this mid-sized excavator model.

Common Symptoms

• Reduced or erratic hydraulic response in specific functions controlled by solenoid valve 6 (often auxiliary hydraulics or specific boom/arm movements)
• Intermittent or complete loss of one hydraulic function while other circuits operate normally
• Warning indicator illuminated on the instrument cluster with code displayed on the monitor panel
• Machine may enter derate mode, limiting engine RPM or hydraulic flow to protect the system
• Unusual clicking or buzzing sounds from the main control valve area when attempting affected functions

Potential Causes

• Damaged or corroded wiring harness between the ECU and solenoid valve 6, particularly at harness routing points near the main control valve where vibration and hydraulic fluid exposure are common
• Failed solenoid coil with internal short circuit or broken windings (common in used excavators with 5,000+ operating hours)
• Connector pin corrosion or bent terminals at the solenoid valve connector, especially on machines operated in wet or coastal environments
• Chafed wiring insulation causing intermittent ground faults at known rub points along the upper frame near the hydraulic tank
• ECU internal driver circuit failure (less common but possible in high-hour machines)
• Poor ground connections at main chassis ground points, creating voltage drop issues

How to Troubleshoot and Fix Code E000105-06

Step 1: Initial Visual Inspection Begin by disconnecting the battery negative terminal for safety. Locate solenoid valve 6 on the main control valve assembly (consult service manual for exact position). Inspect the solenoid connector for oil contamination, corrosion, bent pins, or moisture intrusion. Check the wiring harness from the solenoid back to the ECU, paying special attention to areas where the harness contacts metal surfaces or passes near moving components.

Step 2: Electrical Testing with Multimeter Reconnect the battery and use a digital multimeter (DMM) to measure resistance across the solenoid coil terminals with the connector disconnected. Typical resistance should be 3-7 ohms (verify exact specification in Doosan service literature). A reading of infinite resistance indicates an open coil, while near-zero resistance suggests a short circuit. Next, check for continuity between each solenoid terminal and ground—there should be no continuity; any reading indicates a ground fault.

Step 3: Circuit Voltage and Current Testing Using Doosan diagnostic software (EPOS or equivalent), command solenoid valve 6 to activate while monitoring actual current draw. Compare against specification (typically 1.5-2.5 amps). With the connector attached and solenoid energized, perform a voltage drop test along the power and ground circuits—excessive voltage drop (>0.5V) indicates high resistance from corrosion or damaged wiring.

Step 4: Harness and Connector Repair For used excavators, thoroughly inspect connector terminals using contact cleaner and a wire brush. Replace any corroded pins using OEM connector repair kits. Trace the harness for chafing, particularly where it passes through bulkheads or near the swing bearing. Repair damaged insulation with heat-shrink tubing and dielectric grease on reconnected terminals.

Step 5: Component Replacement and Verification If testing confirms solenoid failure, replace solenoid valve 6 with a genuine Doosan part or verified equivalent. After replacement, clear codes using diagnostic software and perform a hydraulic function test under load. Re-check for code recurrence after 30 minutes of operation. If the code persists with a new solenoid and verified wiring, suspect ECU driver circuit failure requiring controller replacement or professional ECU repair.

---

Disclaimer: This guide provides general diagnostic information for experienced technicians. Always consult the official Doosan service manual for model-specific procedures, torque specifications, and safety protocols. If you lack proper diagnostic tools or experience with high-pressure hydraulic systems, consult a certified Doosan service technician to prevent injury or further machine damage.