Komatsu PC130-6 Fault Code E106: Complete Diagnostic Guide

What is Komatsu PC130-6 Fault Code E106?

Fault Code E106 on the Komatsu PC130-6 indicates a malfunction in the pump control system, specifically related to the hydraulic pump's electronic control solenoid or its associated circuit. This code triggers when the Electronic Control Module (ECM) detects abnormal voltage, current draw, or resistance in the pump flow control solenoid valve circuit.

The PC130-6 uses a sophisticated load-sensing hydraulic system where the ECM continuously adjusts pump output based on operational demand. When E106 appears, this critical feedback loop is compromised, directly affecting fuel efficiency, hydraulic response time, and overall machine productivity. For older PC130-6 excavators, this code often signals wear-related electrical issues rather than complete component failure.

Common Symptoms

• Sluggish hydraulic response across all functions (boom, arm, bucket, swing)
• Warning light illuminated on the instrument cluster with simultaneous reduction in digging force
• Intermittent loss of hydraulic power particularly during combined movements
• Abnormal fuel consumption as the system fails to match pump output to load requirements
• Machine may enter derate mode, limiting engine RPM to protect the hydraulic system

Potential Causes

The most frequent causes for E106 in used PC130-6 excavators include:

• Damaged wiring harness near the main pump—known rubbing point against the pump mounting bracket
• Failed pump control solenoid valve due to internal coil deterioration or contamination buildup
• Corroded electrical connectors at the pump solenoid (common after 5,000+ operating hours)
• ECM power supply issues, including weak ground connections at the chassis mounting point
• Hydraulic contamination causing mechanical binding of the solenoid spool
• Intermittent short circuits in the harness routing through the upper structure swivel area

How to Troubleshoot and Fix Code E106

Step 1: Visual Inspection Inspect the pump control solenoid connector (located on the main hydraulic pump, left side of engine bay). Check for oil contamination, bent pins, or green corrosion. Remove connector and inspect harness for chafing against the pump body—a documented wear point on PC130-6 models.

Step 2: Electrical Testing Using a digital multimeter, measure solenoid resistance at the connector (should read 8-12 ohms at 20°C). Next, check supply voltage with ignition on (should read 24V±2V). Test ground circuit resistance to chassis—must be under 0.5 ohms.

Step 3: Dynamic Circuit Test With engine running at low idle, use Komatsu's KOMTRAX diagnostic software or compatible scan tool to command the solenoid on/off. Monitor current draw (normal: 2.0-2.5A). Erratic readings indicate internal solenoid failure.

Step 4: Harness Continuity For used excavators, trace the harness from ECM (under operator seat) to pump. Pay special attention to wire routing through swivel bearing area where repeated rotation causes conductor fatigue.

Critical for Used Machines: Before replacing the solenoid valve (approximately $450-650), verify all electrical connections and harness integrity. Many E106 codes resolve through connector cleaning and harness repositioning.

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Disclaimer: This guide provides general diagnostic information. Always consult factory service manuals and consider professional assistance for complex hydraulic-electrical issues.