Kobelco SK130-8 Fault Code 6518: Complete Diagnostic Guide

What is Kobelco SK130-8 Fault Code 6518?

Fault Code 6518 on the Kobelco SK130-8 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to a Controller Area Network (CAN) bus communication error between the engine controller and the machine's main electrical system.

This diagnostic trouble code triggers when the ECM detects irregular or interrupted data transmission across the CAN bus network, which serves as the primary communication highway between critical electronic control units. For the SK130-8's Hino J05E engine management system, maintaining stable CAN communication is essential for coordinating fuel injection timing, hydraulic pump control, emission systems, and operator display functions. Communication failures can result in degraded machine performance or complete operational shutdown as a protective measure.

Common Symptoms

• Multiple warning lights illuminating simultaneously on the instrument cluster, including the engine warning lamp and malfunction indicator
• Erratic gauge behavior, with fuel level, coolant temperature, or hydraulic temperature readings fluctuating or going blank
• Intermittent engine derate or power reduction mode engaging unexpectedly during operation
• Loss of monitor display data, where the operator screen shows incomplete information or error messages
• Engine failing to start in severe cases where the ECM cannot verify system parameters through CAN communication

Potential Causes

For used SK130-8 excavators, Code 6518 typically stems from age-related electrical degradation:

• Corroded or moisture-damaged CAN bus connectors, particularly at the ECM harness junction near the engine firewall
• Damaged wiring harness with chafing or broken wires along high-vibration routing points (common at boom base and engine mount areas)
• Faulty terminating resistors in the CAN network causing signal reflection issues
• ECM internal fault or main controller failure, though less common than harness issues
• Voltage irregularities from failing batteries or alternator producing electrical noise on the CAN lines

How to Troubleshoot and Fix Code 6518

Step 1: Visual Inspection of Harness and Connectors Begin by thoroughly inspecting all wiring harness sections between the ECM (located under the operator cab) and the main controller. On used excavators, pay particular attention to areas where harnesses pass through metal grommets or contact frame components. Look for abraded insulation, pinched wires, or connector housings with green corrosion deposits indicating moisture intrusion.

Step 2: Test CAN Bus Voltage and Resistance Using a digital multimeter, measure the resistance between CAN-High and CAN-Low terminals at the ECM connector (with power off). You should read approximately 60 ohms, indicating proper terminating resistor function. With ignition on, measure voltage between each CAN line and ground—expect approximately 2.5 volts on each line at rest. Significant deviation suggests damaged terminating resistors or short circuits.

Step 3: Verify Power Supply and Grounds Check that the ECM receives clean 12-24V power (depending on system voltage) and that all ground connections show less than 0.1 ohms resistance to chassis ground. Corroded ground straps are frequent culprits on used machines, causing voltage fluctuations that disrupt CAN communication.

Step 4: Diagnostic Software Verification Connect Kobelco diagnostic software (or compatible J1939 scan tool) to verify which specific controller is reporting communication loss. The software can isolate whether the engine ECM, main controller, or another module is the non-responsive unit, narrowing replacement decisions.

Step 5: Replace Faulty Components Based on testing, replace damaged harness sections using OEM-spec shielded CAN cable, repair corroded connectors with dielectric grease application, or replace the confirmed faulty controller. Always clear codes and perform a complete communication test cycle before returning to service.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Kobelco service manual for your specific machine serial number and consider professional diagnostic assistance for complex electrical issues. Improper repairs to CAN bus systems can cause additional controller damage.