What is Komatsu PC450-7 Fault Code E113?

Fault Code E113 on the Komatsu PC450-7 excavator indicates a main pump solenoid proportional valve circuit malfunction in the hydraulic system. This code is triggered when the Engine Control Module (ECM) detects abnormal voltage or current flow in the proportional solenoid valve circuit that controls the main hydraulic pump's displacement.

This fault is particularly critical for the PC450-7 because the proportional solenoid valve directly regulates hydraulic pump output based on operational demand. When this circuit malfunctions, the excavator's hydraulic system cannot properly modulate pressure and flow, compromising machine performance, fuel efficiency, and responsive control during digging, lifting, and swing operations.

Common Symptoms

When Code E113 is active on your Komatsu PC450-7, operators typically experience:

• Reduced hydraulic power across all functions, especially noticeable during combined operations like simultaneous boom lift and swing
• Erratic or sluggish response from hydraulic cylinders and motors, with inconsistent speed control
• Warning light illumination on the instrument panel, often accompanied by a audible alarm
• Engine derating in some cases, where the ECM limits engine RPM to protect hydraulic components
• Increased fuel consumption due to inefficient pump displacement control and improper load matching

Potential Causes

The most common technical reasons for Code E113 on used PC450-7 excavators include:

• Damaged solenoid valve wiring harness, particularly near routing points where the harness passes over the hydraulic pump housing (known wear point on this model)
• Failed proportional solenoid valve due to internal coil degradation or contaminated hydraulic oil causing spool sticking
• Corroded or loose electrical connectors at the solenoid valve, especially on machines operated in high-moisture or coastal environments
• Short circuit or open circuit in the valve wiring due to pinching during previous pump removal or maintenance
• ECM internal fault affecting the solenoid driver circuit (less common but possible on higher-hour machines)
• Low supply voltage from degraded battery connections or alternator issues affecting solenoid operation

How to Troubleshoot and Fix Code E113

Step 1: Visual Inspection Begin by inspecting the main pump solenoid valve and its wiring harness for obvious damage. On used excavators, check for harness abrasion where it routes along the pump body—this is a common failure point. Examine the connector at the solenoid for corrosion, bent pins, or hydraulic oil contamination.

Step 2: Electrical Testing Using a digital multimeter, perform resistance and voltage checks. Disconnect the solenoid connector and measure coil resistance; it should typically read 3-7 ohms (consult your service manual for exact specifications). Check for supply voltage (approximately 12V) at the harness connector with the ignition on. Test for continuity between the connector and ECM to identify any open circuits.

Step 3: Solenoid Function Test If electrical values are correct, test the proportional solenoid valve mechanically. Remove the valve from the pump and check for free movement of the spool. Contaminated hydraulic oil in used machines often causes spool sticking. Use Komatsu diagnostic software (KOMTRAX) if available to command the solenoid and observe current draw.

Step 4: Repair or Replace For harness damage, repair using proper weatherproof connectors and route away from heat/friction sources. Replace the solenoid valve if resistance values are out of specification or mechanical binding is detected. When working on used excavators, always replace the O-rings and seals during solenoid installation to prevent future oil leaks.

Disclaimer: This guide provides general diagnostic procedures for Code E113. Hydraulic system repairs require specialized knowledge and tools. Always consult the Komatsu PC450-7 service manual and consider professional assistance for complex electrical diagnostics or if the issue persists after basic troubleshooting.