Sumitomo SH480HD-6 Fault Code 117: Complete Diagnostic Guide

What is Sumitomo SH480HD-6 Fault Code 117?

Fault Code 117 on the Sumitomo SH480HD-6 excavator indicates a malfunction in the engine coolant temperature sensor circuit. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal voltage signal from the coolant temperature sensor, typically indicating an open circuit, short circuit, or sensor failure.

The coolant temperature sensor plays a critical role in the SH480HD-6's engine management system. It provides real-time data to the ECM to optimize fuel injection timing, idle speed, and overall engine performance. When this sensor fails or sends erratic signals, the ECM cannot properly regulate engine temperature, potentially leading to overheating, poor fuel economy, or reduced hydraulic system efficiency.

Common Symptoms

When Code 117 is active on your SH480HD-6, you may experience:

• Check engine light or warning indicator illuminated on the instrument panel
• Engine running in limp mode or derate, limiting power output and hydraulic performance
• Hard starting or extended cranking time, especially in cold conditions
• Rough idle or unstable engine RPM during warm-up
• Cooling fan running continuously at high speed, regardless of actual engine temperature

Potential Causes

The most common technical reasons for Code 117 on used Sumitomo excavators include:

• Faulty coolant temperature sensor due to age-related degradation or internal element failure
• Damaged wiring harness or connector corrosion, particularly at the sensor plug near the engine block
• Open or short circuit in the sensor signal wire, often caused by harness rubbing against engine components
• Poor ground connection at the sensor mounting point or ECM ground terminals
• ECM internal fault (rare, but possible in high-hour machines with electrical system exposure to moisture)

How to Troubleshoot and Fix Code 117

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the engine block (typically near the thermostat housing). Check the wiring harness for visible damage, abrasion, or signs of heat damage. On used excavators, pay special attention to connector pins for corrosion or bent terminals.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across the sensor terminals. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Test the signal wire voltage from the ECM—it should read approximately 5 volts with the sensor disconnected.

Step 3: Harness and Ground Verification Check continuity between the sensor connector and ECM pins to identify any open circuits. Verify ground integrity by measuring resistance between the sensor ground and battery negative—it should be less than 1 ohm. For used machines, inspect harness routing for wear points where cables contact metal edges.

Step 4: Component Replacement If testing confirms sensor failure, replace the coolant temperature sensor with an OEM or quality aftermarket part. Clear the fault code using diagnostic software (such as Sumitomo's proprietary system or compatible tools) and monitor for code recurrence.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sumitomo service manual and consider professional assistance for complex electrical diagnostics or if you're unfamiliar with high-voltage systems.