What is Sumitomo SH200-5 Fault Code 0107?

Fault Code 0107 on the Sumitomo SH200-5 excavator indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Engine Control Module (ECM). This diagnostic trouble code (DTC) is triggered when the ECM receives voltage signals outside the expected range from the coolant temperature sensor, or when the sensor fails to communicate proper resistance values corresponding to actual engine temperature.

This fault is critical because the ECM relies on accurate coolant temperature data to optimize fuel injection timing, govern engine warm-up cycles, and prevent overheating conditions. On used Sumitomo SH200-5 machines, this code often surfaces due to sensor degradation, corroded wiring harnesses, or ECM calibration drift after years of operation in harsh construction environments.

Common Symptoms

• Check engine light or warning lamp illuminated on the operator display panel
• Engine may experience difficult cold starts or prolonged cranking before firing
• Reduced engine performance or power derate mode activation to protect against perceived overheating
• Engine cooling fan running continuously at high speed, even when coolant temperature is normal
• Abnormal temperature gauge readings showing erratic fluctuations or stuck positions

Potential Causes

The most common technical failures triggering Code 0107 on used SH200-5 excavators include:

• Faulty coolant temperature sensor with internal resistance breakdown (common after 5,000+ operating hours)
• Corroded or damaged wiring harness connections at the sensor plug, especially where harness routing contacts frame members or experiences vibration wear
• Broken or frayed sensor wiring between the sensor and ECM, particularly at flex points near the engine mount
• Poor ground connections at ECM mounting points causing voltage reference issues
• Contaminated coolant affecting sensor tip accuracy or air pockets in the cooling system creating false temperature readings
• ECM internal fault (rare but possible in high-hour used machines with electrical system history)

How to Troubleshoot and Fix Code 0107

Step 1: Visual Inspection Begin with the engine cool. Locate the coolant temperature sensor (typically mounted on the engine block or thermostat housing). Inspect the sensor connector for corrosion, moisture intrusion, bent pins, or heat damage. Check the wiring harness for visible abrasion, especially where it routes against metal surfaces—a common wear point on used excavators.

Step 2: Electrical Testing Disconnect the sensor connector. Using a digital multimeter, measure the sensor's resistance with the engine cold (typically 2,000-3,000 ohms at 20°C, but consult Sumitomo specifications). Compare readings as the engine warms. The resistance should decrease smoothly. Then check for continuity in the wiring from sensor to ECM and verify proper ground voltage (should read 5V reference voltage at the sensor connector with key on, engine off).

Step 3: Component Replacement and Verification If sensor resistance is out of specification or wiring shows shorts/opens, replace the faulty component. For used machines, always apply dielectric grease to connector pins before reassembly to prevent future corrosion. After repairs, clear the fault code using Sumitomo diagnostic software or a compatible OBD scan tool, then monitor for code recurrence during a complete heat cycle.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual for your specific serial number and consider professional diagnostic assistance for complex electrical issues.