What is Komatsu PC130-6 Fault Code E315?

Fault Code E315 on the Komatsu PC130-6 indicates a malfunction in the hydraulic pump solenoid valve circuit, specifically related to the pump control system's electrical signal pathway. This code triggers when the Electronic Control Module (ECM) detects abnormal voltage or resistance in the solenoid valve that regulates hydraulic pump output pressure.

The PC130-6 uses a sophisticated load-sensing hydraulic system where the pump solenoid continuously adjusts flow based on operator demand. When E315 appears, the ECM cannot properly modulate pump delivery, potentially forcing the machine into a reduced-performance mode to prevent component damage. This is critical because improper pump control directly affects bucket speed, swing torque, and overall cycle times—compromising productivity on jobsites.

Common Symptoms

• Hydraulic system performance significantly reduced, with sluggish boom, arm, or bucket movements even at high engine RPM
• Amber warning light illuminated on the instrument cluster, often accompanied by alarm beep
• Erratic hydraulic response where functions alternate between normal and weak operation
• Engine may not derate, but hydraulic pump produces audible whining or irregular pressure cycling sounds
• Diagnostic display shows E315 stored in ECM memory when checked with Komatsu diagnostic software

Potential Causes

The E315 code on used PC130-6 excavators typically stems from age-related electrical failures rather than mechanical pump issues. Solenoid valve coil failure is most common, with internal windings breaking down after 8,000+ operating hours. Wiring harness chafing occurs frequently where the pump solenoid harness routes near the swing motor mount—vibration causes insulation wear and intermittent shorts to ground.

Connector corrosion at the pump-mounted solenoid plug is prevalent in machines operating in high-moisture environments. Corroded pins increase circuit resistance beyond ECM tolerances. Additionally, ECM internal driver circuit failure can occur, though less common. On neglected machines, contaminated hydraulic oil causing solenoid valve spool sticking may trigger false electrical fault detection.

How to Troubleshoot and Fix Code E315

Step 1: Visual Inspection
With engine off and battery connected, inspect the pump solenoid connector for corrosion, bent pins, or oil contamination. Check the harness routing from ECM to pump for visible chafing, especially near metal edges and rotating components. Clean connectors with electrical contact cleaner and dielectric grease.

Step 2: Electrical Testing
Using a digital multimeter, disconnect the solenoid connector and measure coil resistance. Typical specification is 8-12 ohms at 20°C; refer to the PC130-6 service manual for exact values. Check harness continuity from ECM connector to solenoid plug—resistance should be under 1 ohm. Measure insulation resistance to ground (should exceed 10 megaohms).

Step 3: Voltage Supply Check
Reconnect components and backprobe the solenoid connector with ignition on. Verify the ECM supplies proper control voltage (typically 12V PWM signal). If voltage is absent but wiring is intact, suspect ECM driver failure. For used excavators, always test under load by commanding pump adjustment through Komatsu diagnostic software while monitoring live data.

Step 4: Component Replacement
If solenoid resistance is out of specification or mechanical sticking is evident, replace the pump solenoid valve assembly (Komatsu part number should be verified for PC130-6 specific application). When replacing, apply anti-seize to threads and new O-rings to prevent future leaks. Clear codes and perform system calibration.

For used machinery, thoroughly inspect all hydraulic system filters and oil condition before finalizing repairs, as contamination often causes repeat failures. Consult a certified Komatsu technician or authorized dealer for complex ECM diagnostics.