Sumitomo SH300-6 Fault Code 560: Complete Diagnostic Guide

What is Sumitomo SH300-6 Fault Code 560?

Fault Code 560 on the Sumitomo SH300-6 excavator indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Electronic Control Module (ECM). This code specifically triggers when the ECM receives voltage signals outside the expected range from the coolant temperature sensor, typically indicating either an open circuit, short circuit, or sensor degradation.

The coolant temperature sensor is critical for this machine's performance because the ECM relies on accurate temperature data to optimize fuel injection timing, control engine warm-up cycles, and prevent overheating damage. On used excavators like the SH300-6, this sensor's reliability directly impacts fuel efficiency, emissions control, and engine longevity.

Common Symptoms

When Code 560 is active, operators typically experience:

• Check Engine light illuminated on the instrument panel with possible temperature warning indicator
• Engine running in default mode with fixed fuel mapping, reducing performance and power output
• Hard starting or extended cranking, especially during cold starts
• Cooling fan running continuously at high speed regardless of actual engine temperature
• Erratic temperature gauge readings or gauge showing maximum temperature immediately upon startup

Potential Causes

The most common technical causes for Code 560 on used SH300-6 excavators include:

• Coolant temperature sensor failure due to age-related internal resistance drift or element corrosion
• Damaged wiring harness near the engine block where heat cycling and vibration cause insulation breakdown
• Corroded or loose electrical connectors at the sensor or ECM—extremely common on machines with 5,000+ operating hours
• ECM internal fault in the sensor input circuit (rare but possible on high-hour machines)
• Coolant contamination causing sensor element coating and inaccurate readings

How to Troubleshoot and Fix Code 560

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor (located on the engine block near the thermostat housing) and its wiring harness. On used excavators, check specifically for harness chafing against the engine block, melted insulation from exhaust heat exposure, and connector corrosion from coolant leaks.

Step 2: Electrical Testing Disconnect the sensor connector and measure resistance across the sensor terminals using a digital multimeter. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Test harness continuity from the sensor connector back to the ECM—resistance should be less than 5 ohms with no shorts to ground.

Step 3: Signal Verification Using Sumitomo diagnostic software or a compatible scan tool, monitor live sensor voltage while the engine warms up. Voltage should decrease smoothly from approximately 4-5 volts (cold) to 0.5-1.5 volts (operating temperature). Erratic readings indicate sensor replacement is needed.

Step 4: Repair or Replace For used machines, clean all connector terminals with electrical contact cleaner before condemning components. Replace the sensor if resistance values are out of specification. Repair any damaged harness sections with heat-resistant wire and protective loom.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sumitomo service manual for your specific machine serial number and consider professional diagnosis for complex electrical issues.