What is Doosan Excavator Fault Code E000105-16?

Fault Code E000105-16 indicates a voltage irregularity or open circuit detected in the engine coolant temperature sensor circuit, specifically a "Data Valid But Below Normal Operating Range" condition. This Doosan-specific diagnostic trouble code (DTC) signals that the Engine Control Module (ECM) is receiving a signal from the coolant temperature sensor that falls outside expected parameters, typically indicating an implausibly low temperature reading or circuit malfunction.

This code is critical for Doosan excavators because the coolant temperature sensor directly influences fuel injection timing, engine warm-up protocols, and protective derate functions. When the ECM cannot accurately monitor engine temperature, it may default to conservative operating modes that reduce performance and efficiency, or worse, fail to protect the engine from overheating conditions.

Common Symptoms

• Check Engine Light or malfunction indicator lamp illuminated on the instrument cluster
• Engine may experience hard starting or rough idle, especially during cold starts
• Reduced engine power or activation of derate mode as the ECM implements failsafe protocols
• Cooling fan running continuously at high speed, even when engine is cold
• Inaccurate or erratic temperature gauge readings on the operator display, often showing abnormally low temperatures

Potential Causes

The most common technical failures triggering E000105-16 in used Doosan excavators include:

• Faulty coolant temperature sensor due to internal element degradation or contamination exposure
• Damaged or corroded wiring harness connections at the sensor plug, particularly common near the engine block where vibration and heat cycles cause wear
• Broken or frayed sensor wires at known rub points along the harness routing path near engine mounts
• Corroded ECM connector pins affecting signal transmission from the sensor circuit
• Low coolant level exposing the sensor element to air rather than coolant fluid
• Failed ECM (rare, but possible in high-hour used machines with moisture intrusion history)

How to Troubleshoot and Fix Code E000105-16

Step 1: Visual Inspection Begin with a thorough physical examination of the coolant temperature sensor and its wiring harness. Check for obvious damage, corrosion on connector terminals, or coolant leaks near the sensor location. On used excavators, pay special attention to harness wear points where cables contact the engine block or frame.

Step 2: Verify Coolant Level Ensure the cooling system is filled to proper capacity. A low coolant condition can expose the sensor tip, causing erroneous low-temperature readings that trigger this code.

Step 3: Test Sensor Resistance Disconnect the coolant temperature sensor connector and use a digital multimeter to measure resistance across the sensor terminals. Compare readings against Doosan specifications (typically 2,000-3,000 ohms at 68°F/20°C). Values significantly outside this range indicate sensor failure.

Step 4: Check Circuit Voltage With the sensor disconnected and ignition on, measure voltage at the harness connector leading to the ECM. You should see approximately 5 volts reference voltage from the ECM. No voltage indicates wiring issues or ECM problems.

Step 5: Inspect Wiring Continuity Test continuity between the sensor connector and ECM pins using wiring diagrams specific to your Doosan model. For used machines, carefully inspect the entire harness for internal breaks caused by repeated flexing or rodent damage.

Step 6: Clear Code and Monitor After repairs, use Doosan diagnostic software (G-SCAN or equivalent) to clear the fault code and monitor live data during engine warm-up to confirm proper sensor operation across the temperature range.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Doosan service manual for your specific excavator model and consider professional diagnostic assistance for complex electrical issues or if you're unsure about any procedure.