What is Komatsu PC200LC-7 Fault Code E315?

Fault Code E315 on the Komatsu PC200LC-7 indicates a malfunction in the fuel injection control system, specifically related to the fuel injector solenoid circuit for cylinder #5. This diagnostic trouble code (DTC) is triggered when the engine control module (ECM) detects an abnormal electrical signal—either an open circuit, short circuit, or incorrect resistance—in the injector solenoid wiring or the injector itself.

This code is particularly critical for the PC200LC-7's SAA6D102E-2 engine because improper fuel injection timing and delivery directly impact combustion efficiency, engine power output, and emissions compliance. When cylinder #5 fails to receive proper fuel delivery signals, the engine experiences uneven performance and potential long-term damage to internal components.

Common Symptoms

• Engine misfiring or rough idle, particularly noticeable during cold starts or under load
• Illuminated malfunction indicator lamp on the monitor panel with error code E315 displayed
• Reduced engine power (derate mode), limiting the excavator's ability to perform heavy digging or lifting operations
• Increased black or white smoke from the exhaust, indicating incomplete combustion
• Poor fuel economy and difficulty maintaining consistent RPM under working conditions

Potential Causes

The most common technical causes for E315 on used PC200LC-7 excavators include:

• Faulty fuel injector solenoid on cylinder #5 due to internal coil failure or mechanical wear
• Damaged wiring harness between the ECM and injector, especially at known rub points near the valve cover or along the engine block where harnesses experience vibration and heat cycling
• Corroded or loose electrical connectors at the injector plug, common in machines with high hours or exposure to moisture
• ECM internal driver circuit failure, though less common than external wiring issues
• Poor quality repairs from previous owners, including incorrect wire gauge or improper connector crimps

How to Troubleshoot and Fix Code E315

Step 1: Visual Inspection Begin by inspecting the injector wiring harness from the ECM to cylinder #5. Look for abraded insulation, pinched wires near mounting brackets, or evidence of previous repairs. On used excavators, check connector terminals for corrosion (green/white deposits) or bent pins.

Step 2: Electrical Testing Using a digital multimeter, disconnect the injector connector and measure the solenoid resistance. The Komatsu specification requires 0.4-0.8 ohms at 20°C. Next, check for continuity between the ECM connector pins and the injector terminals to identify breaks in the wiring.

Step 3: Voltage Testing With the key on but engine off, verify the ECM provides proper battery voltage (approximately 24V) to the injector circuit. If voltage is absent, suspect an ECM driver circuit issue or blown fuse.

Step 4: Component Replacement If resistance and continuity tests pass but symptoms persist, replace the fuel injector for cylinder #5. For used machines with over 8,000 hours, consider replacing the entire injector harness to prevent recurring failures from aged insulation.

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual and consider professional diagnostic services for complex electrical troubleshooting or ECM programming requirements.