What is Doosan Excavator Fault Code E000174-16?

Fault Code E000174-16 indicates a "Hydraulic Oil Temperature Sensor Circuit - Voltage Below Normal or Shorted to Ground" condition in Doosan excavators. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects abnormally low voltage from the hydraulic oil temperature sensor circuit, typically below 0.5 volts, suggesting a short circuit to ground or complete sensor failure.

This code is critical for Doosan excavators because the hydraulic oil temperature sensor provides essential data to the ECM for managing hydraulic system performance, protecting components from overheating, and optimizing operational efficiency. When this sensor fails or provides incorrect readings, the machine cannot properly monitor hydraulic fluid conditions, potentially leading to reduced performance or component damage.

Common Symptoms

• Hydraulic temperature warning light illuminated on the instrument cluster, even when hydraulic oil is cold
• Reduced hydraulic system performance or machine entering derate mode to protect components
• ECM defaulting to fail-safe values, causing sluggish operation of boom, arm, and bucket functions
• Intermittent loss of hydraulic power or unpredictable hydraulic response during operation
• Engine management system may limit RPM or activate limp mode in severe cases

Potential Causes

• Damaged or corroded wiring harness between the hydraulic oil temperature sensor and ECM, particularly at known rub points near the hydraulic tank mounting bracket
• Failed hydraulic oil temperature sensor due to internal short circuit or age-related deterioration (common in used excavators with 5,000+ operating hours)
• Corroded or loose connector pins at the sensor connection point, especially on machines exposed to harsh environments
• Chafed wiring where the harness passes through the frame or contacts sharp edges
• Water intrusion into the sensor connector causing short to ground
• ECM internal fault (rare) affecting the sensor input circuit

How to Troubleshoot and Fix Code E000174-16

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor (typically mounted on the hydraulic tank or main control valve). Inspect the sensor connector for corrosion, bent pins, moisture, or physical damage. On used excavators, carefully trace the wiring harness back to the ECM, checking for chafing, cuts, or rub points against frame members or hydraulic lines.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure resistance across the sensor terminals. A functional sensor should read approximately 2,000-3,000 ohms at room temperature (consult your Doosan service manual for exact specifications). Also measure voltage supply from the ECM harness side—you should see approximately 5 volts reference voltage. If voltage is absent or incorrect, suspect ECM or harness issues.

Step 3: Ground Circuit Verification With the sensor disconnected, check for continuity between the sensor signal wire and ground. Any continuity (less than 10 ohms) indicates a short to ground in the harness. For used machines, pay special attention to harness sections near hydraulic cylinders and rotating components where vibration causes insulation wear.

Step 4: Sensor Replacement and Verification If the sensor tests faulty, replace it with a genuine Doosan part or quality equivalent. Clear the fault code using Doosan diagnostic software (DX-Tool or compatible scan tool) and monitor during operation. If the code returns immediately, focus troubleshooting on the wiring harness and ECM connections.

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Doosan service manual for your specific model. If you're uncomfortable performing electrical diagnostics, contact a certified Doosan technician to prevent further damage to your used excavator's electrical system.