What is Kobelco SK130-8 Fault Code 6568?

Fault Code 6568 on the Kobelco SK130-8 excavator indicates a malfunction in the exhaust gas recirculation (EGR) valve position sensor circuit or abnormal EGR valve response. This code typically triggers when the Electronic Control Module (ECM) detects that the EGR valve's actual position does not match the commanded position, or when the position sensor signal falls outside the expected voltage range.

The EGR system is critical for reducing nitrogen oxide (NOx) emissions by recirculating a portion of exhaust gases back into the combustion chamber. On the SK130-8's engine, proper EGR valve operation ensures compliance with emission standards while maintaining optimal engine performance. When Code 6568 appears, the ECM may limit engine power to prevent potential damage or excessive emissions, directly impacting your machine's productivity and fuel efficiency.

Common Symptoms

• Engine derating or noticeable power loss, especially under heavy load conditions
• Amber warning light illuminated on the instrument cluster, possibly accompanied by a check engine indicator
• Rough idle or irregular engine performance, particularly during cold starts
• Increased black smoke from the exhaust due to incomplete combustion
• Reduced hydraulic response as the engine control system limits RPM to protect components

Potential Causes

The most common technical causes for Code 6568 on used SK130-8 excavators include:

• EGR valve position sensor failure due to carbon buildup or internal wear after extended operating hours
• Damaged or corroded wiring harness connections at the EGR valve connector—a known wear point on this model due to proximity to heat and vibration sources
• Mechanical sticking of the EGR valve caused by carbon deposits preventing smooth operation
• ECM calibration issues or outdated software requiring flash updates
• Contaminated electrical connectors from engine oil leaks or environmental exposure common in older machines

How to Troubleshoot and Fix Code 6568

Step 1: Visual Inspection Begin by examining the EGR valve wiring harness for obvious damage, chafing, or corroded connectors. On used excavators, check specifically where the harness routes near the engine block for heat-related insulation breakdown. Clean all connector pins with electrical contact cleaner and inspect for bent terminals.

Step 2: Sensor Circuit Testing Using a digital multimeter, check the position sensor signal voltage at the EGR valve connector (typically 0.5-4.5 volts depending on valve position). Compare readings with Kobelco diagnostic software specifications. Test harness continuity between the ECM and EGR valve—resistance should be less than 5 ohms per wire.

Step 3: EGR Valve Physical Inspection Remove the EGR valve and inspect for carbon deposits restricting movement. Clean carefully with appropriate EGR cleaner, ensuring the valve moves freely through its full range. Check the actuator motor operation using the diagnostic tool's bidirectional control functions.

Step 4: Component Replacement If testing reveals a faulty position sensor or seized valve mechanism, replacement is necessary. On used machines, always replace the entire valve assembly rather than individual sensors to ensure reliability. Clear codes with diagnostic software and perform a relearn procedure per manufacturer specifications.

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