Sumitomo SH380LHD-6 Fault Code 117: Complete Diagnostic Guide

What is Sumitomo SH380LHD-6 Fault Code 117?

Fault Code 117 on the Sumitomo SH380LHD-6 indicates a malfunction in the hydraulic oil temperature sensor circuit. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects an abnormal voltage signal from the hydraulic oil temperature sensor, typically indicating an open circuit, short circuit, or sensor failure.

This code is critical for the SH380LHD-6's performance because the hydraulic oil temperature directly affects system efficiency, component longevity, and operational safety. The ECM uses temperature data to adjust hydraulic flow rates, activate cooling fans, and prevent thermal damage to pumps, motors, and seals. Ignoring this fault can lead to catastrophic hydraulic system failure, especially in used excavators where component wear is accelerated.

Common Symptoms

When Code 117 is active on your Sumitomo SH380LHD-6, operators typically experience:

• Warning light illumination on the instrument cluster, often accompanied by a continuous or intermittent alarm
• Erratic hydraulic oil temperature gauge readings showing unusually high, low, or fluctuating temperatures
• Reduced hydraulic performance as the ECM enters a derate mode to protect system components
• Cooling fan running continuously at maximum speed regardless of actual oil temperature
• Sluggish operation during cold starts or diminished responsiveness under heavy loads

Potential Causes

The most common technical reasons for Code 117 on used SH380LHD-6 excavators include:

• Hydraulic oil temperature sensor failure due to thermal cycling and age-related degradation
• Damaged or corroded wiring harness at known rub points near the hydraulic tank mounting bracket
• Loose or oxidized electrical connectors at the sensor or ECM interface
• Broken sensor mounting allowing the sensor to lose contact with hydraulic fluid
• ECM internal fault (rare, but possible in high-hour machines with electrical system stress)
• Aftermarket sensor incompatibility if previous repairs used non-OEM components

How to Troubleshoot and Fix Code 117

Step 1: Visual Inspection Begin by inspecting the hydraulic oil temperature sensor located on the hydraulic tank. Check for physical damage, oil leaks around the sensor body, and secure mounting. On used excavators, examine the wiring harness for chafing against the tank or frame, particularly where it routes near hydraulic lines.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. A functioning sensor typically shows 2,000-3,000 ohms at room temperature (consult your service manual for exact specifications). Check for continuity in the wiring from sensor to ECM, and verify ground integrity at the ECM connection point.

Step 3: Voltage Signal Verification With the sensor connected and ignition on (engine off), backprobe the sensor connector to measure supply voltage (should read approximately 5 volts from the ECM). If voltage is absent or incorrect, trace the circuit for open wires or ECM issues.

Step 4: Component Replacement If testing confirms sensor failure, replace with a genuine Sumitomo OEM sensor to ensure proper calibration. For used excavators, always apply dielectric grease to connector pins to prevent future corrosion. Clear the fault code using diagnostic software and verify proper operation through a temperature cycle.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sumitomo service manual for your specific machine serial number and seek professional assistance for complex electrical diagnostics or if you lack proper training and tools.