What is Kobelco SK135SRLC-2 Fault Code E013?

Fault Code E013 on the Kobelco SK135SRLC-2 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 caused by an open circuit, short circuit, or sensor failure. The coolant temperature sensor is critical for this Kobelco excavator's performance because it directly influences fuel injection timing, engine warm-up cycles, and protective shutdown protocols. When this sensor provides inaccurate data, the ECM cannot properly regulate engine temperature, potentially leading to overheating, poor fuel efficiency, or engine protection mode activation.

Common Symptoms

When Code E013 is active on your SK135SRLC-2, operators typically experience:

• Engine warning light illuminated on the instrument panel, often accompanied by an audible alarm
• Engine running in derate mode or reduced power output to prevent potential damage
• Difficulty starting in cold conditions or extended cranking times during morning startups
• Cooling fan running continuously at high speed, regardless of actual engine temperature
• Erratic temperature gauge readings or gauge stuck at minimum/maximum positions

Potential Causes

The E013 code on used Kobelco SK135SRLC-2 excavators is commonly triggered by:

• Coolant temperature sensor failure due to internal element degradation (common after 5,000+ operating hours)
• Damaged or corroded wiring harness connections at the sensor plug, especially where the harness contacts the engine block
• Connector pin corrosion from coolant leaks or moisture intrusion in the engine compartment
• Broken or chafed wires between the sensor and ECM, particularly at routing points near the turbocharger heat shield
• Failed ECM (rare, but possible in machines with electrical system history or previous water damage)

How to Troubleshoot and Fix Code E013

Step 1: Visual Inspection Begin by locating the coolant temperature sensor on the engine block (typically near the thermostat housing). Inspect the sensor connector for obvious corrosion, bent pins, or moisture. Check the wiring harness routing for signs of rubbing against the engine, heat damage, or previous repairs with electrical tape.

Step 2: Electrical Testing Disconnect the sensor and use a multimeter to check resistance. At room temperature (68°F/20°C), the sensor should read approximately 2,000-3,000 ohms. Test the harness for continuity from the sensor plug back to the ECM connector. Check for shorts to ground—resistance should be infinite (OL on meter).

Step 3: Voltage Supply Check With the ignition on and sensor disconnected, measure voltage at the harness connector. You should see approximately 5 volts reference voltage from the ECM. If voltage is absent, trace the harness for breaks or check ECM power supply circuits.

Step 4: Component Replacement For used excavators, replace the sensor even if readings appear marginal—sensors degrade over time. Use genuine Kobelco or OEM-equivalent parts. Apply dielectric grease to connector terminals before reconnection to prevent future corrosion. Clear codes using Kobelco diagnostic software or a compatible scanner and verify repair with a test cycle.

Disclaimer: This guide provides general troubleshooting information. Always consult the Kobelco SK135SRLC-2 service manual and consider professional diagnostic assistance for complex electrical issues or if you're unfamiliar with high-voltage systems.