What is Sumitomo SH210-6 Fault Code 113?

Fault Code 113 on the Sumitomo SH210-6 excavator indicates a malfunction in the engine coolant temperature sensor circuit. This code is triggered when the Engine Control Module (ECM) detects an abnormal voltage signal from the coolant temperature sensor, typically indicating either an open circuit, short circuit, or sensor reading outside the normal operating range.

The coolant temperature sensor is a critical component that monitors engine temperature and sends voltage signals to the ECM. The ECM uses this data to adjust fuel injection timing, idle speed, and activate cooling fan operation. On the SH210-6 with its Isuzu 6BG1 engine, proper coolant temperature monitoring is essential for preventing overheating, optimizing fuel efficiency, and ensuring the engine operates within safe thermal parameters. When this sensor circuit fails, the ECM cannot accurately manage engine temperature, potentially leading to performance issues or engine damage.

Common Symptoms

When Code 113 is active on your SH210-6, you may experience:

• Engine warning light illuminated on the instrument panel
• Hard starting or extended cranking time, especially in cold conditions
• Poor fuel economy due to the ECM defaulting to a fixed temperature value
• Erratic cooling fan operation – fan may run constantly or not engage when needed
• Black smoke from exhaust caused by improper fuel mixture compensation
• Engine running rough at idle or during warm-up phase

Potential Causes

Several factors can trigger Code 113 on used SH210-6 excavators:

• Faulty coolant temperature sensor – internal resistance drift or complete failure (common after 5,000+ hours)
• Damaged wiring harness – particularly at routing points near the engine block where vibration causes wire chafing
• Corroded or loose connector at the sensor or ECM connection points
• Shorted sensor ground wire touching the engine block or frame
• Low coolant level exposing the sensor tip to air instead of coolant
• ECM internal fault – less common but possible in high-hour machines
• Aftermarket sensor installation with incorrect resistance specifications

How to Troubleshoot and Fix Code 113

Step 1: Visual Inspection Begin by checking the coolant level in the radiator and overflow tank. Locate the coolant temperature sensor on the engine block (typically near the thermostat housing on the 6BG1 engine). Inspect the sensor connector for corrosion, bent pins, or moisture intrusion. On used excavators, pay special attention to the wiring harness routing from the sensor to the ECM – look for rubbed-through insulation, particularly where wires contact metal brackets or the engine block.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure sensor resistance. At 20°C (68°F), resistance should typically read 2,000-3,000 ohms; at 80°C (176°F), approximately 300-400 ohms (consult your service manual for exact specifications). Test the wiring harness continuity from the sensor connector back to the ECM. Check for short circuits to ground by measuring resistance between each wire and the engine block (should read infinite resistance).

Step 3: Component Replacement and Verification If the sensor fails resistance testing or wiring shows damage, replace the faulty component with OEM or equivalent quality parts. When installing a new sensor, apply thread sealant appropriate for coolant systems and torque to specification (typically 15-20 Nm). For used excavators with corroded connectors, clean contacts with electrical contact cleaner and apply dielectric grease to prevent future corrosion. After repairs, clear the fault code using diagnostic software (Sumitomo-compatible scan tool or universal heavy equipment scanner) and perform a test run, monitoring coolant temperature readings.

Disclaimer: This guide provides general troubleshooting information. Always consult the Sumitomo SH210-6 service manual for exact specifications. If you're uncomfortable performing electrical diagnostics, consult a qualified heavy equipment technician to prevent further damage to the ECM or electrical system.