Kobelco SK130-8 Fault Code 6571: Complete Diagnostic Guide

What is Kobelco SK130-8 Fault Code 6571?

Fault Code 6571 on the Kobelco SK130-8 excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to a CAN (Controller Area Network) bus communication error between the engine controller and hydraulic controller.

This code triggers when the ECM detects insufficient or corrupted data transmission along the CAN bus network, which is the digital nervous system connecting all electronic control units on your excavator. The CAN bus allows critical systems—engine management, hydraulic controls, and monitoring systems—to share real-time operational data. When communication breaks down, your SK130-8 cannot properly coordinate engine performance with hydraulic demand, leading to compromised machine efficiency and potential safety concerns.

For used excavators, this fault is particularly significant because degraded wiring harnesses and corroded connectors are common culprits that disrupt the low-voltage signals required for proper CAN communication.

Common Symptoms

When Code 6571 is active on your Kobelco SK130-8, you may experience:

• Warning light illumination on the instrument cluster, often accompanied by a check engine light or communication error indicator
• Reduced hydraulic response or sluggish operation due to improper engine-hydraulic coordination
• Intermittent power loss or engine derating, especially under load when multiple systems demand coordination
• Erratic gauge behavior including fuel level, temperature, or pressure readings fluctuating abnormally
• Difficulty starting or rough idle as the ECM struggles to receive proper sensor feedback

Potential Causes

The most common technical causes for Code 6571 on used SK130-8 excavators include:

• Damaged CAN bus wiring harness, particularly at flex points near the engine compartment or along the boom where cables experience constant movement and vibration
• Corroded or loose connector pins at the ECM, hydraulic controller, or junction box connections—moisture intrusion is common in older machines
• Faulty Engine Control Module (ECM) with internal circuit board degradation or capacitor failure
• Hydraulic controller malfunction preventing proper signal transmission to the engine management system
• Poor grounding connections causing voltage reference issues that corrupt digital signals
• Aftermarket modifications or improper repairs that compromised CAN bus termination resistors (120-ohm resistors required at network endpoints)

How to Troubleshoot and Fix Code 6571

Step 1: Visual Inspection of Wiring and Connectors

Begin by thoroughly inspecting the CAN bus wiring harness from the ECM to the hydraulic controller. On used excavators, focus on areas where harnesses contact metal surfaces, pass through grommets, or bend repeatedly. Look for chafed insulation, pinched wires, or exposed copper. Disconnect and examine all connectors for corrosion, bent pins, or moisture. Clean contacts with electrical contact cleaner and apply dielectric grease before reconnecting.

Step 2: Test CAN Bus Circuit Continuity and Resistance

Using a digital multimeter, measure resistance between CAN-High and CAN-Low terminals at the ECM connector (with harness disconnected). You should read approximately 60 ohms, indicating proper termination resistors are in place. Check continuity from ECM to hydraulic controller—any open circuit indicates a wiring break. Measure voltage on CAN-High (should read approximately 2.5-3.5V with key on, engine off) and CAN-Low (approximately 1.5-2.5V). Significant deviation suggests controller failure.

Step 3: Utilize Kobelco Diagnostic Software

Connect Kobelco-specific diagnostic software (such as JUNO software or equivalent dealer-level scanner) to access live data streams and communication status. Monitor whether the ECM can actively communicate with the hydraulic controller. Perform bi-directional tests to command hydraulic functions while observing ECM response. This isolates whether the fault lies in wiring, ECM, or the hydraulic controller itself.

Step 4: Check Grounding Points and Power Supply

Verify that both the ECM and hydraulic controller have clean, tight ground connections to the chassis. Measure battery voltage at both controllers—should be 12-14V with engine off, 13.5-14.5V running. Poor grounds or voltage drops exceeding 0.2V indicate corroded ground straps common in used machines.

Step 5: Replace Faulty Components

If diagnostics isolate a failed controller, replacement is necessary. For used excavators, inspect replacement ECM programming—it must match your machine's software version. When replacing wiring harnesses, ensure proper routing away from heat sources and moving components, and verify termination resistor installation.

---

Disclaimer: This guide provides general troubleshooting information for Code 6571. Excavator electrical systems involve complex diagnostics that may require manufacturer-specific tools and training. Always consult qualified heavy equipment technicians or authorized Kobelco service centers for definitive diagnosis and repair, especially when working with used machinery where undocumented modifications may exist.