What is Doosan DX300LC-9C Fault Code E000105-04?

Fault Code E000105-04 indicates a FNR (Forward-Neutral-Reverse) solenoid valve circuit failure with a voltage below normal range in the Doosan DX300LC-9C excavator's transmission control system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects abnormally low voltage in the FNR solenoid valve circuit, typically below 2.0 volts during operation when it should read between 10-14 volts.

This code is critical for the DX300LC-9C because the FNR solenoid controls directional movement in machines equipped with optional travel motors or specific hydraulic transmission configurations. When this circuit malfunctions, the ECM cannot properly regulate hydraulic pressure to the transmission system, potentially causing erratic travel behavior or complete loss of directional control. For used excavators, this fault often indicates age-related electrical degradation rather than mechanical failure.

Common Symptoms

• Travel function warning light illuminated on the instrument cluster with possible audible alarm
• Erratic or delayed response when switching between forward and reverse travel directions
• Loss of power during travel operations or machine refusing to move in one or both directions
• ECM entering derate mode, limiting engine RPM to protect the transmission system
• Intermittent fault occurrence that clears and returns, especially during cold starts or wet conditions

Potential Causes

The most common technical causes for E000105-04 in used DX300LC-9C excavators include:

• Damaged or corroded wiring harness at known rub points near the swing bearing or along the main chassis frame where the FNR solenoid harness routes
• Failed FNR solenoid valve coil with internal short circuit or open winding (resistance should read 12-18 ohms)
• Corroded or loose connector pins at the solenoid valve connector (C-104) or ECM connector (C-201)
• Chafed wiring causing intermittent short-to-ground, particularly common in 2014-2017 model years
• Low system voltage from failing alternator or weak batteries affecting solenoid activation
• ECM internal fault (rare) in the solenoid driver circuit

How to Troubleshoot and Fix Code E000105-04

Step 1: Visual Inspection and Connector Check Begin by locating the FNR solenoid valve on the transmission control valve body (typically mounted on the left side of the machine near the swing motor). Disconnect the solenoid connector and inspect for corrosion, bent pins, or moisture intrusion. On used excavators, this connector often shows green corrosion due to water ingress. Clean with electrical contact cleaner and apply dielectric grease.

Step 2: Solenoid Resistance and Voltage Testing Using a digital multimeter, measure resistance across the solenoid terminals—it should read 12-18 ohms. Next, with the key on and engine off, check for battery voltage (12V) at the harness connector supply wire (usually red/white wire). If voltage is present but drops significantly under load, suspect wiring resistance or poor ground connection.

Step 3: Harness Continuity and Ground Path Verification Trace the solenoid harness from the valve back to the ECM, checking for chafing or pinch points especially where it passes through the swing bearing area and along the main frame rails. Test continuity between the ECM connector pin and solenoid connector. Verify the ground circuit has less than 0.5 ohms resistance to chassis ground. For used machines, inspect the main ground strap connection points for corrosion.

Step 4: Solenoid Replacement or ECM Diagnosis If wiring and connections test normal, replace the FNR solenoid valve (Doosan part number 336-00048A or equivalent). Clear codes using Doosan DMS (Diagnostic Master System) software or compatible diagnostic tool. If the fault persists with a new solenoid and verified wiring, the ECM driver circuit may be damaged and require ECM replacement or professional repair.

---

Disclaimer: This guide provides general troubleshooting procedures for informational purposes. Always consult the official Doosan service manual for your specific serial number and consider professional diagnosis for complex electrical issues. Improper repairs may cause additional damage or safety hazards.