Sumitomo SH260LC-6 Fault Code 113: Complete Diagnostic Guide

What is Sumitomo SH260LC-6 Fault Code 113?

Fault Code 113 on the Sumitomo SH260LC-6 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 predetermined threshold range from the coolant temperature sensor, typically between 0.5V and 4.5V on this model.

The coolant temperature sensor plays a critical role in the SH260LC-6's performance management. It directly influences fuel injection timing, engine protection protocols, and hydraulic oil temperature regulation. When this sensor circuit fails, the ECM cannot properly manage engine temperature, potentially leading to overheating, reduced fuel efficiency, or unnecessary engine derating to protect components.

Common Symptoms

• Engine warning light illuminated on the instrument cluster, often accompanied by a temperature warning icon
• Engine running in limp mode or reduced power output to prevent potential overheating damage
• Difficulty starting the engine, particularly in cold weather conditions, due to improper fuel mixture calculations
• Cooling fan running continuously at high speed, regardless of actual engine temperature
• Abnormal temperature gauge readings showing extremely high or low temperatures inconsistent with actual operating conditions

Potential Causes

The most common technical causes for Code 113 on used SH260LC-6 excavators include:

• Coolant temperature sensor failure due to age-related degradation or internal element breakdown (common after 5,000+ operating hours)
• Damaged or corroded wiring harness connections at the sensor plug, particularly where the harness routes near the engine block and experiences heat cycling
• Shorted or open circuits in the sensor wiring, often caused by harness chafing against engine components or the boom cylinder
• Corrosion on ECM connector pins (specifically the sensor input terminals), common in machines operated in coastal or high-humidity environments
• Failed ECM temperature input circuit, though less common than sensor or wiring issues
• Low coolant level causing intermittent sensor exposure to air instead of coolant

How to Troubleshoot and Fix Code 113

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor location (typically on the engine block near the thermostat housing). Check the connector for corrosion, moisture intrusion, or damaged pins. On used excavators, examine the entire wiring harness from sensor to ECM for abrasion points, especially where it passes near moving components or heat sources.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance. At room temperature (68°F/20°C), resistance should read approximately 2,000-3,000 ohms. Test the harness continuity from the sensor connector to the ECM—resistance should be less than 5 ohms. Check for shorts to ground (should read infinite resistance).

Step 3: Sensor Replacement and Verification If the sensor tests outside specifications or the harness shows damage, replace the faulty component. For used machines, always apply dielectric grease to connector pins before reassembly to prevent future corrosion. Clear the fault code using Sumitomo diagnostic software or a compatible scan tool, then monitor for code recurrence during a complete heat cycle.

Professional Disclaimer: This guide provides general diagnostic procedures. Always consult the official Sumitomo service manual for your specific serial number range. If you're uncomfortable performing electrical diagnostics or the code persists after following these steps, consult a certified Sumitomo technician to prevent potential engine damage.