Sumitomo SH210-6 Fault Code 117: Complete Diagnostic Guide

What is Sumitomo SH210-6 Fault Code 117?

Fault Code 117 on the Sumitomo SH210-6 excavator indicates an Engine Coolant Temperature (ECT) Sensor Circuit malfunction, specifically a high voltage or open circuit condition detected by the Engine Control Module (ECM). This code triggers when the ECM receives abnormally high voltage readings from the coolant temperature sensor circuit, typically above 4.5 volts, suggesting the sensor is disconnected, shorted, or the wiring harness has failed.

The ECT sensor plays a critical role in the SH210-6's engine management system by monitoring coolant temperature and relaying data to the ECM for fuel injection timing, idle speed control, and overheat protection. When this sensor circuit fails, the ECM operates in default mode, which can lead to reduced performance, increased fuel consumption, and potential engine damage from inadequate temperature monitoring.

Common Symptoms

When Code 117 is active on your Sumitomo SH210-6, you may experience:

• Check Engine Light or malfunction indicator illuminated on the instrument panel
• Engine running cooler than normal or temperature gauge reading incorrectly (often showing maximum or minimum)
• Rough idle or hard starting, especially in cold conditions, due to improper fuel mixture
• Increased fuel consumption as the ECM defaults to a rich fuel map without accurate temperature data
• Reduced engine power or performance degradation during operation

Potential Causes

The most common technical reasons for Code 117 on used SH210-6 excavators include:

• Damaged or disconnected ECT sensor connector due to vibration or improper maintenance
• Broken or corroded wiring in the sensor harness, particularly at flex points near the engine block
• Failed coolant temperature sensor with internal open circuit (common in machines with 8,000+ operating hours)
• Corroded connector pins at the ECM or sensor side caused by coolant leaks or moisture intrusion
• Chafed wiring harness rubbing against engine components or frame members (known issue on older SH210-6 models)
• ECM internal fault (rare, but possible in high-hour machines)

How to Troubleshoot and Fix Code 117

Step 1: Visual Inspection Begin by locating the ECT sensor on the engine block (typically near the thermostat housing). Inspect the sensor connector for corrosion, bent pins, or moisture. On used excavators, check the entire wiring harness from sensor to ECM for chafing, cuts, or damage from previous repairs. Pay special attention to areas where the harness contacts metal surfaces or moving components.

Step 2: Electrical Testing Disconnect the ECT sensor connector and use a digital multimeter to 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). If the reading shows infinite resistance (open circuit) or zero ohms (short circuit), replace the sensor.

Step 3: Circuit Continuity Check With the sensor disconnected, check voltage at the harness connector. You should see approximately 5 volts reference voltage from the ECM with the ignition on. If voltage is absent or incorrect, trace the signal wire and ground wire back to the ECM, checking for breaks or shorts. Measure resistance between the sensor ground wire and chassis ground (should be less than 1 ohm).

Step 4: Connector and Harness Repair For used excavators, thoroughly clean all connector pins with electrical contact cleaner and inspect for corrosion. Apply dielectric grease to prevent future moisture intrusion. Repair any damaged harness sections using heat-shrink solder connectors rather than crimp connectors for better durability in high-vibration environments.

Step 5: Clear Code and Verify After repairs, clear the fault code using Sumitomo diagnostic software or a compatible OBD scanner. Run the engine through multiple temperature cycles and monitor for code recurrence. If Code 117 returns immediately, suspect ECM issues requiring professional diagnosis.

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Disclaimer: This guide provides general troubleshooting information for Sumitomo SH210-6 excavators. Always consult your machine's official service manual and consider professional assistance for complex electrical diagnostics. Improper repairs can lead to further damage or safety hazards.