Doosan DX220LC-9C Fault Code E000105-05: Complete Diagnostic Guide

What is Doosan DX220LC-9C Fault Code E000105-05?

Fault Code E000105-05 indicates a hydraulic pump control system malfunction, specifically related to the main pump displacement sensor circuit experiencing an abnormal voltage signal or communication error with the excavator's Electronic Control Unit (ECU).

This code directly affects the hydraulic pump displacement control system, which regulates the swash plate angle of the main hydraulic pumps on the DX220LC-9C. The displacement sensor continuously monitors pump output and sends signals to the ECU to optimize hydraulic flow based on operator demand and engine load. When this circuit fails, the excavator cannot properly match hydraulic power to work requirements, leading to reduced efficiency and potential overheating of hydraulic components. For the DX220LC-9C's advanced load-sensing hydraulic system, this sensor is critical for maintaining the precise pump control that defines this machine's fuel efficiency and smooth operation.

Common Symptoms

When Code E000105-05 is active, operators typically experience:

• Warning light illumination on the instrument cluster with potential error message display on the monitor
• Sluggish or inconsistent hydraulic response across all functions (boom, arm, bucket, swing)
• Reduced digging force and slower cycle times, particularly noticeable during heavy excavation work
• Engine RPM fluctuations or hunting as the ECU attempts to compensate for incorrect pump displacement feedback
• Increased fuel consumption due to the system defaulting to a fixed, less-efficient pump displacement setting

Potential Causes

The most common technical failures triggering this fault code include:

• Displacement sensor internal failure due to contamination from hydraulic fluid particulates or moisture intrusion (common in machines with 5,000+ operating hours)
• Wiring harness damage at known rub points near the main pump mounting area where harness routing passes close to the engine block or hydraulic lines
• Corroded or loose connector pins at the sensor plug or ECU connection points, particularly on excavators operated in coastal or high-humidity environments
• ECU communication errors caused by voltage irregularities from aging batteries, poor ground connections, or aftermarket electrical accessories
• Hydraulic pump mechanical wear creating abnormal displacement that the sensor reads as out-of-range values

How to Troubleshoot and Fix Code E000105-05

Step 1: Visual Inspection and Connector Check

Begin by locating the main pump displacement sensor on the side of the hydraulic pump assembly. Inspect the wiring harness from sensor to ECU for obvious damage, particularly where it passes near hot engine components or moving parts. On used excavators, check for harness insulation wear, oil contamination on connectors, and physical damage. Disconnect the sensor connector and inspect pins for corrosion, bent terminals, or moisture. Clean contacts with electrical contact cleaner and verify proper seating when reconnecting.

Step 2: Electrical Testing with Diagnostic Tools

Using a digital multimeter, perform resistance and voltage checks. With ignition ON and engine OFF, measure supply voltage at the sensor connector—should read approximately 5 volts (reference voltage from ECU). Check sensor ground circuit for continuity to chassis ground (should be less than 1 ohm). Measure sensor signal output voltage while manually moving the pump displacement mechanism (if accessible)—voltage should vary smoothly between approximately 0.5-4.5 volts. Connect Doosan DMS (Diagnostic Master System) or compatible diagnostic software to read live sensor data and compare actual displacement readings to commanded values.

Step 3: Component Replacement and System Verification

If electrical tests reveal out-of-specification readings, replace the displacement sensor with a genuine Doosan part (aftermarket sensors often cause intermittent faults). Before installation, inspect the sensor mounting boss for metal debris or hydraulic contamination that could damage the new sensor. After replacement, clear fault codes using diagnostic software and perform a pump calibration procedure following Doosan service manual specifications. Test the excavator under load to verify proper hydraulic response. For used machines, consider replacing the entire harness section if multiple wire chafing points are evident, as this prevents recurring failures.

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Disclaimer: This guide provides general diagnostic information for experienced technicians. Always consult the official Doosan service manual for your specific serial number range and follow proper safety procedures. Complex hydraulic system repairs may require specialized tools and factory-trained technicians to prevent equipment damage or injury.