Doosan DX150LC-9C Fault Code E000737-06: Complete Diagnostic Guide

What is Doosan DX150LC-9C Fault Code E000737-06?

Fault Code E000737-06 indicates a Hydraulic Pump Solenoid Valve Circuit malfunction, specifically detecting an abnormal voltage or open circuit condition in the main hydraulic pump's proportional control solenoid. This code is triggered when the ECM (Engine Control Module) detects that the electrical signal to the hydraulic pump's solenoid valve is outside the manufacturer's specified range of 0.5-4.5 volts.

This fault directly impacts the DX150LC-9C's load-sensing hydraulic system, which regulates pump output based on operational demand. The solenoid valve controls hydraulic flow and pressure, making it critical for coordinating engine speed with hydraulic work requirements. When this circuit fails, the excavator cannot properly match hydraulic power to the load, resulting in inefficient operation and potential performance limitations.

Common Symptoms

• Reduced hydraulic power across all functions (boom, arm, bucket, swing) with noticeably slower cycle times
• Erratic engine RPM fluctuations during hydraulic operations, especially under load
• Warning light illumination on the instrument cluster, often accompanied by error code display
• Hydraulic system operating in default/limp mode, restricting pump output to a fixed low-pressure setting
• Increased fuel consumption due to inefficient engine-pump coordination

Potential Causes

The E000737-06 code typically results from electrical circuit failures rather than mechanical hydraulic issues:

• Broken or frayed wiring in the solenoid harness, particularly at flex points near the pump mounting location where vibration causes wire fatigue
• Corroded or loose connector pins at the solenoid valve or ECM connection points—common in used machines exposed to moisture
• Failed proportional solenoid coil within the pump assembly, showing open circuit or incorrect resistance (should read 10-15 ohms)
• ECM internal driver circuit failure, though less common than external wiring issues
• Damaged harness routing where cables contact sharp edges or moving components on older DX150LC-9C models

How to Troubleshoot and Fix Code E000737-06

Step 1: Visual Inspection and Connector Check Begin by inspecting the solenoid valve connector located on the main hydraulic pump (right side of engine). Disconnect the connector and examine pins for corrosion, bent contacts, or moisture intrusion. On used excavators, check the harness routing from pump to ECM for rub-through points against frame members or hydraulic lines. Clean connectors with electrical contact cleaner and apply dielectric grease.

Step 2: Solenoid Resistance Testing Using a digital multimeter, measure resistance across the solenoid coil terminals with the connector disconnected. Specification should be 10-15 ohms at 20°C. An open circuit (infinite resistance) or short circuit (near-zero resistance) indicates solenoid failure requiring pump solenoid replacement.

Step 3: Circuit Voltage and Continuity Testing With ignition ON and engine OFF, backprobe the solenoid connector to measure supply voltage (should read battery voltage, approximately 12-14V). Check signal wire voltage from ECM during cranking—it should vary between 0.5-4.5V. Test ground circuit continuity to chassis, which must show less than 1 ohm resistance. If voltage/continuity is incorrect at the solenoid but wiring checks good, use Doosan DMS (Diagnostic Master System) software to monitor ECM output signals and verify internal ECM driver function.

Step 4: Harness Repair for Used Equipment For used excavators, carefully trace the entire harness from pump to ECM, checking for hidden damage under wire loom or abraded insulation. Pay special attention to areas where harnesses pass through bulkheads or near rotating components. Repair any damaged sections with proper gauge wire and heat-shrink connections rather than replacing entire harnesses when possible.

Disclaimer: This guide provides general diagnostic information. Always consult the official Doosan service manual for your specific serial number and consider professional diagnosis for complex electrical issues or if unfamiliar with high-voltage systems.