Sumitomo SH210LC-5LR Fault Code 107: Complete Diagnostic Guide

What is Sumitomo SH210LC-5LR Fault Code 107?

Fault Code 107 on the Sumitomo SH210LC-5LR indicates an Engine Coolant Temperature (ECT) Sensor Circuit malfunction or abnormal high-temperature reading. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects a voltage signal from the coolant temperature sensor that falls outside the acceptable range, typically indicating either an open circuit, short circuit, or sensor reading above critical thresholds.

The ECT sensor is critical for this excavator's performance because it directly influences fuel injection timing, engine protection protocols, and hydraulic oil temperature management. When the ECM cannot accurately monitor coolant temperature, the machine may enter derate mode to prevent catastrophic engine damage, significantly reducing operational productivity.

Common Symptoms

When Code 107 is active on your SH210LC-5LR, operators typically experience:

• Engine warning light or check engine lamp illuminated on the instrument cluster
• Automatic engine power reduction (derate mode) limiting swing speed and digging force
• Engine overheating or false high-temperature readings even when coolant feels cool to touch
• Difficulty starting in cold conditions due to incorrect fuel enrichment calculations
• Radiator cooling fan running continuously at maximum speed regardless of actual temperature

Potential Causes

The most common technical failures causing Code 107 in used Sumitomo excavators include:

• Worn or corroded ECT sensor connector (especially on machines with 5,000+ operating hours)
• Failed coolant temperature sensor due to thermal cycling and age-related drift
• Damaged wiring harness between the sensor and ECM, particularly near engine vibration points
• Corroded ground connections at the ECM or sensor mounting location
• Coolant contamination causing sensor element fouling or premature failure
• ECM internal circuit fault (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code 107

Step 1: Visual Inspection Begin by locating the ECT sensor (typically mounted on the engine block near the thermostat housing). Inspect the connector for corrosion, bent pins, or moisture intrusion—common issues in used excavators. Check the wiring harness for chafing against engine components or heat damage near the exhaust manifold.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across the sensor terminals. At room temperature (68°F/20°C), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Also check for continuity between the sensor connector and the ECM pins to identify broken wires.

Step 3: Live Circuit Testing With the ignition on but engine off, back-probe the sensor connector to measure voltage supply from the ECM (typically 5 volts). A reading significantly different suggests ECM issues or harness shorts. For used machines, pay special attention to ground circuit integrity—clean and tighten all ground connections.

Step 4: Replacement and Verification If testing confirms sensor failure, replace with OEM or equivalent quality parts. After installation, clear codes using diagnostic software compatible with Sumitomo systems and perform a cold-start test cycle to verify proper operation. Monitor coolant temperature readings during warm-up to ensure they follow normal progression curves.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sumitomo service manual for your specific machine serial number. If you lack proper diagnostic tools or experience with high-voltage electrical systems, seek assistance from a certified heavy equipment technician to avoid injury or further damage.