What is Kobelco SK350LC-8 Fault Code E013?

Kobelco SK350LC-8 Fault Code E013 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 relates to the engine's thermal management system, which is critical for preventing overheating and maintaining optimal hydraulic oil viscosity in this 35-ton excavator model.

The coolant temperature sensor sends vital data to the ECM to regulate engine performance, fan speed, and fuel injection timing. When E013 triggers, the ECM detects either an open circuit, short circuit, or implausible temperature signal from the sensor. For the SK350LC-8's Hino J05E engine, accurate coolant temperature monitoring is essential—improper readings can cause premature engine wear, reduced hydraulic system efficiency, and potential catastrophic overheating damage to cylinder heads or gaskets.

Common Symptoms

When fault code E013 is active on your Kobelco SK350LC-8, you may experience:

• Engine warning light illuminated on the dashboard display panel
• Hard starting conditions or extended cranking time, especially in cold weather
• Cooling fan running continuously at maximum speed, even when the engine is cold
• Reduced engine power or derate mode activation to protect the engine from perceived overheating
• Black smoke from exhaust due to improper fuel mixture compensation based on faulty temperature data

Potential Causes

The most common technical causes for E013 on used SK350LC-8 excavators include:

• Failed coolant temperature sensor due to internal resistance drift (common after 5,000+ operating hours)
• Corroded or loose wiring connectors at the sensor harness connection point near the thermostat housing
• Damaged sensor wiring harness caused by rubbing against the engine block or exhaust manifold heat shield—a known wear point on this model
• Contaminated coolant causing sensor element coating or degradation
• ECM internal fault or corrupted calibration data (rare, but possible in high-hour machines)
• Faulty ground connection at the engine block ground strap affecting sensor signal return

How to Troubleshoot and Fix Code E013

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor location (typically on the engine block near the thermostat housing). Check for physical damage, coolant leaks, or corrosion on the two-pin connector. On used excavators, carefully examine the entire wiring harness routing for abrasion points where it contacts metal surfaces—this is particularly common near the alternator bracket on SK350LC-8 models.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance at various temperatures. At 20°C (68°F), resistance should typically read between 2,000-3,000 ohms; at 80°C (176°F), approximately 300-400 ohms. Compare readings against Kobelco specifications in the service manual. Also test for continuity in the wiring from the sensor connector back to the ECM—any reading above 5 ohms indicates harness damage.

Step 3: Connector and Ground Verification Clean all connector terminals with electrical contact cleaner and apply dielectric grease to prevent future corrosion. Verify the engine ground strap connection is tight and free of rust. For used machines, this connection often loosens over time due to vibration.

Step 4: Coolant System Check Inspect coolant condition—contaminated or incorrect coolant mix can cause sensor failures. If coolant appears rusty or degraded, perform a complete flush before replacing sensors.

Step 5: Component Replacement If testing confirms sensor failure, replace with a genuine Kobelco or OEM-equivalent temperature sensor (part number specific to SK350LC-8). After replacement, use Kobelco diagnostic software to clear the fault code and verify proper sensor signal voltage (typically 0.5-4.5V depending on temperature).

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Disclaimer: This guide provides general diagnostic information for Kobelco SK350LC-8 fault code E013. Always consult the official Kobelco service manual and consider professional assistance from a certified heavy equipment technician for complex electrical diagnostics or if you're uncomfortable performing these procedures.