Sumitomo SH210-5 Fault Code 107: Complete Diagnostic Guide

What is Sumitomo SH210-5 Fault Code 107?

Fault Code 107 on the Sumitomo SH210-5 excavator indicates a malfunction in the Engine Coolant Temperature (ECT) Sensor circuit. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects an abnormal voltage signal from the coolant temperature sensor, typically indicating an open circuit, short circuit, or sensor reading outside the acceptable range.

The ECT sensor plays a critical role in engine management by monitoring coolant temperature and sending data to the ECM. This information directly affects fuel injection timing, idle speed control, and engine protection systems. On used Sumitomo SH210-5 machines, this code can lead to improper engine performance, increased fuel consumption, and potential overheating if left unaddressed.

Common Symptoms

When Code 107 is active, operators typically experience:

• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Hard starting conditions, especially during cold weather operation
• Rough idle or unstable engine RPM due to incorrect fuel mapping
• Engine derate mode or reduced power output as a protective measure
• Inaccurate coolant temperature gauge readings or gauge stuck at minimum/maximum

Potential Causes

The most common technical reasons for Code 107 on used SH210-5 excavators include:

• Failed ECT sensor due to internal resistance drift or element failure (common after 5,000+ operating hours)
• Damaged wiring harness near the thermostat housing where vibration and heat cause insulation breakdown
• Corroded or loose connector pins at the sensor plug, especially on machines operated in wet or marine environments
• Shorted sensor ground wire touching the engine block or frame
• ECM internal circuit failure (rare, but possible on high-hour machines)
• Coolant contamination causing sensor element fouling or premature failure

How to Troubleshoot and Fix Code 107

Step 1: Visual Inspection Begin by inspecting the ECT sensor located near the thermostat housing on the engine block. Check for physical damage, coolant leaks, or corrosion. On used excavators, carefully examine the wiring harness for rubbing points against the engine or frame, particularly where the harness passes near moving components or hot exhaust areas.

Step 2: Electrical Testing Disconnect the ECT sensor connector and use a digital multimeter to measure sensor resistance. At 68°F (20°C), resistance should typically read between 2,000-3,000 ohms (consult your service manual for exact specifications). Check for continuity between sensor terminals and ground—there should be no continuity, indicating proper insulation.

Step 3: Circuit Verification With the sensor disconnected, measure voltage at the harness connector. You should see approximately 5 volts on the signal wire with ignition on. Check the ground circuit for less than 0.5 ohms resistance to chassis ground. For used machines, probe the connector pins for corrosion and apply dielectric grease after cleaning.

Step 4: Component Replacement If testing confirms sensor failure, replace the ECT sensor with an OEM or high-quality aftermarket unit. Always use a new copper crush washer and torque to specification (typically 15-20 ft-lbs). Clear the fault code using diagnostic software and perform a test run, monitoring live data to verify proper temperature readings.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Sumitomo service manual for your specific machine serial number. If you're uncomfortable performing electrical diagnostics, contact a certified Sumitomo dealer or qualified heavy equipment technician to prevent further damage.