Doosan Excavator Fault Code E001180-02: Complete Diagnostic & Repair Guide

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What is Doosan Excavator Fault Code E001180-02?

Doosan fault code E001180-02 indicates a voltage rationality fault on the Engine Coolant Temperature (ECT) sensor circuit — specifically, the signal voltage has dropped below the expected minimum threshold (out-of-range low condition).

This fault is governed by the ECM (Engine Control Module), which continuously monitors the ECT sensor's output signal. When the voltage falls below approximately 0.2V DC, the ECM flags the circuit as implausible and logs this code.

On Doosan machines, accurate coolant temperature data is critical for fuel injection timing, engine protection derating, and fan control logic. A compromised ECT signal can trigger unnecessary shutdowns or — more dangerously — allow the engine to overheat undetected.

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Common Symptoms

• Amber or red warning light illuminated on the cluster monitor panel
• Engine entering protection/derate mode, reducing power output unexpectedly
• Erratic or frozen temperature gauge reading on the display (often stuck at minimum)
• Cooling fan running at maximum speed continuously, regardless of actual engine temperature
• Fault code stored in ECM memory, even after machine restart

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Potential Causes

• Failed or shorted ECT sensor — internal short to ground pulling voltage below threshold
• Damaged wiring harness — chafing against the engine block, turbo heat shield, or chassis frame is common on high-hour used machines
• Corroded or moisture-contaminated connector at the ECT sensor plug
• Open circuit or broken wire within the sensor signal or ground wire
• ECM pin damage — bent, pushed-back, or corroded terminals inside the ECM connector

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How to Troubleshoot and Fix Code E001180-02

Step 1 — Retrieve and Document the Fault Connect Doosan's proprietary diagnostic software (DIAPS or DoosanCONNECT) to the machine's diagnostic port. Confirm the active/inactive status of E001180-02 and check freeze-frame data for conditions when the fault occurred.

Step 2 — Physical Inspection First (Critical on Used Machines) Before touching a multimeter, physically trace the ECT sensor harness from the sensor to the ECM. On used excavators, look specifically for harness rub points near the exhaust manifold and engine mount brackets. Inspect the sensor connector for corrosion, moisture ingress, or spread pins.

Step 3 — Electrical Testing With the connector unplugged, use a digital multimeter to measure sensor resistance across its terminals. A healthy ECT sensor typically reads 2.0–2.5 kΩ at ambient temperature. An open circuit or near-zero reading confirms sensor failure.

Step 4 — Circuit Continuity Check Check signal wire continuity from the sensor connector back to the ECM harness connector. Voltage at the sensor reference pin should read approximately 5V DC with the key ON, engine OFF.

Step 5 — Repair or Replace Repair any damaged wiring, clean corroded connectors with electrical contact cleaner, and replace the ECT sensor if confirmed faulty. Clear the fault code and perform a functional test cycle.

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Disclaimer: This guide is intended for qualified heavy equipment mechanics and experienced technicians. Always consult the official Doosan service manual for your specific machine serial number before performing repairs. When in doubt, contact an authorized Doosan service dealer.