What is Kobelco SK130-8 Fault Code 20108?

Fault Code 20108 on the Kobelco SK130-8 excavator indicates a malfunction in the engine oil pressure sensor circuit or abnormally low oil pressure detection. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects an irregular voltage signal from the oil pressure sensor or when actual oil pressure falls below the manufacturer's specified threshold for safe operation.

This code is critical for the SK130-8's Hino J05E diesel engine performance because proper oil pressure ensures adequate lubrication to critical engine components including crankshaft bearings, camshaft, and turbocharger. When this fault activates, the ECM may initiate protective measures to prevent catastrophic engine damage. In used excavators, this code often appears due to sensor degradation, wiring issues, or actual mechanical oil system problems that develop over thousands of operating hours.

Common Symptoms

• Engine warning light illuminated on the instrument panel with possible audible alarm
• Engine power derate or automatic shutdown in severe cases to protect internal components
• Erratic oil pressure gauge readings or gauge stuck at zero despite engine running
• Low oil pressure warning appearing intermittently during warm-up or at idle speeds
• Rough idle or hesitation under load as the ECM adjusts fuel delivery in response to perceived oil pressure issues

Potential Causes

The most common technical causes for Code 20108 on used SK130-8 excavators include:

• Failed oil pressure sensor - The sensor's internal diaphragm or electrical components deteriorate with age and heat cycling
• Wiring harness damage - The sensor connector and wiring near the oil filter housing are prone to oil contamination, corrosion, and physical abrasion from vibration
• Low engine oil level - Actual insufficient oil due to leaks, consumption, or missed service intervals
• Worn oil pump - In high-hour machines, internal pump wear reduces pressure output, especially at idle
• Clogged oil filter or pickup screen - Restriction in the oil system from contamination or sludge buildup
• ECM calibration issues - Rare, but software corruption or incorrect pressure threshold settings can trigger false codes

How to Troubleshoot and Fix Code 20108

Step 1: Verify Oil Level and Condition Check the engine oil level with the machine on level ground. Top off if low and inspect for contamination, metal particles, or coolant mixing. Change oil and filter if the oil appears degraded or if service is overdue beyond manufacturer intervals.

Step 2: Inspect the Oil Pressure Sensor and Wiring Locate the oil pressure sensor on the engine block near the oil filter assembly. Disconnect the electrical connector and inspect for corrosion, oil intrusion, or bent pins—common issues in used excavators. Check the wiring harness for abrasion points where it contacts the engine or frame. Use a multimeter to test connector continuity from the sensor pins back to the ECM (typically should show less than 5 ohms resistance).

Step 3: Test Sensor Output and Signal Voltage With the sensor connected, use a Kobelco diagnostic scanner or compatible tool to monitor live oil pressure readings. Compare sensor voltage output at idle and under load to factory specifications (typically 0.5-4.5V range depending on pressure). A sensor reading constant voltage regardless of engine RPM indicates sensor failure.

Step 4: Verify Actual Oil Pressure Install a mechanical oil pressure gauge in the sensor port to confirm actual pressure. At operating temperature, idle pressure should be minimum 10-15 PSI and 40-60 PSI at rated RPM. If mechanical pressure is correct but the code persists, replace the oil pressure sensor. If actual pressure is low, inspect the oil pump, relief valve, and internal engine bearings for wear.

Step 5: Clear Code and Monitor After repairs, clear the fault code using diagnostic software and operate the machine through multiple heat cycles. On used excavators with high hours, persistent low oil pressure despite sensor replacement may indicate oil pump wear or bearing clearance issues requiring engine overhaul.

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Disclaimer: This guide provides general troubleshooting information. Always consult the Kobelco SK130-8 service manual for model-specific procedures and specifications. If you lack proper diagnostic tools or experience, contact a certified Kobelco technician to prevent misdiagnosis or engine damage.