What is Kobelco SK130-8 Fault Code 6564?

Fault Code 6564 on the Kobelco SK130-8 excavator indicates a malfunction in the engine coolant temperature sensor circuit, specifically an intermittent or erratic signal being sent to the Engine Control Module (ECM). This code triggers when the ECM detects voltage readings outside the normal operating parameters or receives inconsistent data from the coolant temperature sensor (CTS).

The coolant temperature sensor is critical for the Kobelco SK130-8's fuel injection system and emission controls. It directly affects fuel mapping, idle speed control, and the diesel particulate filter (DPF) regeneration cycles. When this sensor provides faulty data, the ECM cannot properly adjust fuel delivery or manage engine protection protocols, potentially leading to decreased performance, increased fuel consumption, and accelerated engine wear in used machines.

Common Symptoms

Operators experiencing Code 6564 typically report:

• Engine warning light illuminated on the instrument panel, sometimes intermittently
• Hard starting conditions, especially during cold starts when accurate temperature readings are most critical
• Erratic idle speed or rough running during warm-up periods
• Poor fuel economy due to incorrect fuel enrichment calculations
• Failed or delayed DPF regeneration cycles, leading to secondary exhaust system issues

Potential Causes

The most common technical failures triggering this code on used SK130-8 excavators include:

• Corroded or loose connector pins at the coolant temperature sensor—extremely common in machines with 3,000+ operating hours
• Damaged sensor wiring harness due to rubbing against the engine block near the thermostat housing (known wear point on this model)
• Failed coolant temperature sensor itself, often from coolant contamination or internal element degradation
• ECM ground circuit issues affecting multiple sensor readings simultaneously
• Coolant system air pockets after improper service, causing intermittent sensor exposure

How to Troubleshoot and Fix Code 6564

Step 1: Visual Inspection Begin by inspecting the CTS connector located near the thermostat housing on the cylinder head's left side. Look for corrosion, bent pins, or moisture intrusion. On used excavators, this connector frequently suffers from coolant seepage. Clean contacts with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing Using a digital multimeter, backprobe the sensor connector with the key on, engine off. You should read approximately 5 volts on the signal wire (typically green/white). Check sensor resistance: at 68°F (20°C), resistance should be 2,000-3,000 ohms. Compare readings to Kobelco's specification chart for your engine temperature.

Step 3: Harness Inspection Trace the wiring harness from sensor to ECM, checking for abrasion points where it passes near the exhaust manifold bracket. This is a documented failure point on SK130-8 models. Use electrical tape and protective loom on any exposed areas.

Step 4: Sensor Replacement If electrical values are out of specification, replace the coolant temperature sensor using a genuine Kobelco part (Part #YN52S00023P1). Ensure proper torque (12-18 ft-lbs) and verify the system is properly bled of air.

Step 5: Clear Code and Monitor Use Kobelco diagnostic software or a compatible J1939 scanner to clear the fault code. Monitor live data during a complete warm-up cycle to confirm stable voltage readings (should transition smoothly from ~4.5V cold to ~1.5V hot).

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Disclaimer: This guide provides general troubleshooting information. For used excavators with complex electrical issues or under warranty, consult a certified Kobelco technician or authorized service center for proper diagnosis and repair.