What is Sumitomo SH220LC-6 Fault Code 113?

Fault Code 113 on the Sumitomo SH220LC-6 excavator indicates an Engine Coolant Temperature (ECT) Sensor Circuit High Voltage condition. This diagnostic trouble code is triggered when the Engine Control Module (ECM) detects a voltage signal from the coolant temperature sensor that exceeds the normal operating range (typically above 4.5-4.8 volts).

The ECT sensor is a critical component that monitors engine coolant temperature and sends variable resistance signals to the ECM. On the SH220LC-6's engine management system, this data directly influences fuel injection timing, idle speed control, and engine protection protocols. When Code 113 activates, the ECM may default to a predetermined coolant temperature value, potentially causing inefficient combustion, increased fuel consumption, and inadequate engine protection against overheating.

Common Symptoms

When Fault Code 113 is active on your Sumitomo SH220LC-6, you may experience:

• Check Engine Light or malfunction indicator lamp illuminated on the instrument cluster
• Engine running in cold-start mode continuously, resulting in rough idle and black smoke from exhaust
• Hard starting conditions, especially when the engine is warm
• Poor fuel economy and reduced hydraulic system responsiveness due to improper fuel mapping
• ECM recording multiple instances of the fault in diagnostic history, even if symptoms are intermittent

Potential Causes

The most common technical reasons for Code 113 on used Sumitomo excavators include:

• Open circuit in ECT sensor wiring harness caused by wire breaks, particularly near the engine block where vibration and heat stress are highest
• Failed coolant temperature sensor with internal open circuit (resistance reading shows infinite ohms)
• Corroded or damaged sensor connector pins at the sensor plug—common in machines with coolant leaks or exposure to moisture
• Chafed wiring at known rub points along the main engine harness, especially where it routes near sharp edges or moving components
• Poor ground connection at the ECM or sensor ground circuit
• ECM internal fault (rare, but possible in high-hour machines with electrical system stress)

How to Troubleshoot and Fix Code 113

Step 1: Visual Inspection Begin by inspecting the ECT sensor and its wiring harness for obvious damage. On used excavators, check for coolant residue around the sensor indicating leaks that may have damaged the connector. Examine the harness routing from sensor to ECM for wear points, particularly where it contacts the engine block or frame rails.

Step 2: Sensor and Circuit Testing Disconnect the ECT sensor connector and measure resistance across the sensor terminals using a digital multimeter (DMM). At room temperature (68°F/20°C), resistance should typically read 2,000-3,000 ohms (consult service manual for exact specifications). If the reading shows infinite resistance (open circuit), replace the sensor. Next, check for continuity in the wiring between the sensor connector and ECM pins—any open circuit indicates harness repair is needed.

Step 3: Voltage Supply Check With the sensor disconnected and ignition on (engine off), measure voltage at the ECM supply wire at the sensor connector. You should see approximately 5 volts reference voltage. If voltage is present at the connector but the code persists with a known-good sensor installed, suspect ECM internal issues or intermittent harness faults. For used machines, always inspect connector terminals for corrosion and apply dielectric grease after cleaning.

Step 4: Clear Codes and Verify Repair After repairs, clear fault codes using Sumitomo diagnostic software or compatible scan tool, then operate the machine through multiple temperature cycles to confirm the fix.

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Disclaimer: This guide provides general troubleshooting information. Always consult the Sumitomo SH220LC-6 service manual for exact specifications and safety procedures. For complex electrical diagnostics or if you're uncomfortable working with engine management systems, seek assistance from a certified heavy equipment technician.