Komatsu PC750LC-7 Fault Code E215: Complete Diagnostic Guide

What is Komatsu PC750LC-7 Fault Code E215?

Fault Code E215 indicates a malfunction in the hydraulic pump control system, specifically related to the pump flow control solenoid valve circuit or its associated wiring harness. This code is triggered when the Electronic Control Module (ECM) detects an abnormal voltage or current reading from the pump control solenoid, which regulates hydraulic flow based on operational demands.

In the PC750LC-7, this system is critical for maintaining optimal hydraulic performance and fuel efficiency. The pump flow control solenoid adjusts the swash plate angle of the main hydraulic pumps, directly affecting machine responsiveness and power delivery. When this circuit fails, the excavator may default to a fixed displacement mode, significantly impacting productivity.

Common Symptoms

When Code E215 is active, operators typically experience:

• Reduced hydraulic power across all functions, with noticeably slower cycle times
• Warning light illumination on the monitor panel, often accompanied by an audible alarm
• Loss of fine control during precision work, as the pump cannot modulate flow properly
• Increased fuel consumption due to the pump operating at maximum displacement regardless of load
• Intermittent performance issues that may worsen as the machine warms up or during high-demand operations

Potential Causes

The most common technical causes for E215 in used PC750LC-7 excavators include:

• Solenoid valve failure due to internal coil degradation or contaminated hydraulic oil causing valve sticking
• Wiring harness damage at known rub points near the pump mounting area or along the main boom
• Corroded or loose connector pins at the solenoid valve connection, especially on machines operating in wet or corrosive environments
• ECM voltage supply issues affecting the 12V or 24V power circuit to the solenoid
• Hydraulic contamination causing mechanical binding of the solenoid spool
• Previous repair attempts with incorrect wiring or non-OEM replacement parts

How to Troubleshoot and Fix Code E215

Step 1: Visual Inspection Begin by inspecting the pump control solenoid valve and its wiring harness for obvious damage. On used excavators, check for harness chafing where cables pass near the hydraulic pump housing and swing bearing. Look for oil contamination on connectors, which indicates seal failures.

Step 2: Electrical Testing Using a digital multimeter, measure the solenoid coil resistance (typically 10-15 ohms for Komatsu solenoids). Disconnect the harness connector and check for voltage supply from the ECM (should read battery voltage with key on). Test for continuity in the ground circuit and inspect for voltage drops exceeding 0.5V, which indicate corroded connections.

Step 3: Functional Testing With Komatsu diagnostic software (KOMTRAX or PC-based tools), command the solenoid valve to actuate while monitoring current draw. Normal operation shows 0.8-1.2 amps. Erratic readings suggest internal solenoid failure. For used machines, perform a hydraulic oil analysis to check for contamination that may affect solenoid operation.

Step 4: Component Replacement If testing confirms solenoid failure, replace with genuine Komatsu parts (part number specific to PC750LC-7). Before installation, flush the hydraulic circuit and inspect the pump control valve body for scoring or debris. Apply dielectric grease to all connector pins to prevent future corrosion.

---

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific machine serial number and seek professional assistance for complex hydraulic system repairs.