What is Sumitomo SH220LC-6 Fault Code 563?

Fault Code 563 on the Sumitomo SH220LC-6 excavator indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Engine Control Module (ECM). This code specifically relates to the sensor that monitors engine coolant temperature and transmits data to the ECM for proper engine management and protection.

The coolant temperature sensor plays a critical role in the SH220LC-6's Isuzu engine management system. It directly influences fuel injection timing, idle speed control, and the activation of the engine protection system. When this sensor fails or provides incorrect readings, the ECM cannot properly regulate engine temperature, potentially leading to overheating, poor fuel economy, or engine damage. For used excavators, this sensor circuit is particularly vulnerable due to age-related corrosion and wiring deterioration from heat exposure near the engine block.

Common Symptoms

• Engine warning light or check engine light illuminated on the instrument panel
• Engine running cooler or hotter than normal operating temperature (185-205°F)
• Increased fuel consumption and black smoke from exhaust due to improper fuel mapping
• Hard starting when the engine is cold, or rough idle during warm-up
• Engine derate mode activation in severe cases, limiting machine performance to protect components

Potential Causes

The most common technical causes for Code 563 on used SH220LC-6 excavators include:

• Faulty coolant temperature sensor due to internal resistance drift or element failure (common after 5,000+ operating hours)
• Damaged or corroded wiring harness between the sensor and ECM, particularly at connector pins exposed to coolant leaks
• Poor electrical ground connection at the sensor mounting point due to rust or paint buildup on the engine block
• ECM voltage supply issues providing incorrect reference voltage (typically should be 5V) to the sensor
• Coolant contamination causing sensor element coating or physical damage from glycol breakdown in older machines

How to Troubleshoot and Fix Code 563

Step 1: Visual Inspection Begin by locating the coolant temperature sensor on the engine block (typically near the thermostat housing on Isuzu engines). Inspect the wiring harness for obvious damage, melting, chafing against metal surfaces, or corrosion at the connector. Check for coolant leaks that may have contaminated the electrical connection. On used excavators, pay special attention to harness routing where vibration causes wire-to-frame contact.

Step 2: Electrical Testing Disconnect the sensor and use a digital multimeter to measure resistance across the sensor terminals. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult Sumitomo service manual for exact specifications). Test the harness continuity from the sensor connector back to the ECM—resistance should be less than 5 ohms. Check for short circuits to ground by measuring resistance between each wire and chassis ground (should read infinite/OL).

Step 3: Voltage Supply Check With the ignition on and sensor disconnected, measure reference voltage at the harness connector. You should see approximately 5V from the ECM. If voltage is absent or incorrect, inspect the ECM power supply and ground circuits. For used machines, clean all ground connections with a wire brush and apply dielectric grease.

Step 4: Component Replacement If the sensor tests faulty, replace it with an OEM or quality aftermarket unit. Always replace the sealing washer to prevent coolant leaks. After installation, clear the fault code using Sumitomo diagnostic software or a compatible scan tool, then monitor coolant temperature during a complete warm-up cycle to verify proper operation.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual for your specific machine serial number and consult qualified diesel technicians for complex electrical diagnostics or repairs beyond your expertise level.