What is Komatsu PC360-7 Fault Code E315?

Fault Code E315 on the Komatsu PC360-7 indicates a malfunction in the hydraulic pump solenoid valve circuit, specifically a short circuit or open circuit condition detected by the Engine Control Module (ECM). This code typically signals that the proportional solenoid valve controlling main hydraulic pump displacement is not receiving proper electrical signals or has failed internally.

The PC360-7 uses sophisticated electronic-controlled hydraulic pumps that adjust displacement based on load demand. When the ECM cannot communicate properly with the pump solenoid, the machine loses its ability to optimize hydraulic flow efficiently. This directly impacts fuel economy, cycle times, and overall machine performance. For used excavators, this fault often stems from electrical deterioration rather than component failure, making proper diagnosis essential before ordering expensive replacement parts.

Common Symptoms

• Warning light illumination on the instrument cluster with reduced engine power output
• Sluggish hydraulic response during combined functions (swing plus boom operation)
• Engine automatically limiting RPM to approximately 1,500-1,800 RPM (derate mode)
• Erratic pump pressure resulting in inconsistent bucket or arm speed
• Intermittent code activation that may clear and return during operation, especially when machine vibrates or operates on uneven terrain

Potential Causes

The E315 code on used PC360-7 excavators most frequently results from wiring harness degradation near the main pump mounting area where cable flexing and vibration cause conductor fatigue. Connector corrosion at the pump solenoid plug (typically a 3-pin Deutsch-style connector) ranks as the second most common cause, particularly on machines operated in wet or coastal environments.

Other probable causes include:

• Solenoid valve internal coil failure (resistance typically should read 8-12 ohms)
• ECM power supply issues affecting multiple circuits simultaneously
• Damaged pins or backed-out terminals in the main harness connector
• Aftermarket electrical modifications interfering with factory ground circuits

How to Troubleshoot and Fix Code E315

Step 1: Connect Diagnostic Software
Use Komatsu KOMTRAX Plus or compatible diagnostic software to capture freeze frame data. Note whether the fault is currently active or stored, and check if multiple codes are present, which may indicate a power supply problem rather than component-specific failure.

Step 2: Inspect Wiring Harness and Connectors
Locate the pump solenoid connector near the main hydraulic pump (typically mounted on the left side of the pump housing). Disconnect and inspect for green corrosion, bent pins, or oil contamination. On used excavators, pay special attention to the harness routing under the cab—this is a known rub point on PC360-7 machines where insulation wears through against structural steel.

Step 3: Test Solenoid Resistance and Voltage Supply
Using a digital multimeter, measure solenoid coil resistance across the connector terminals (ECM disconnected). Compare readings against factory specifications (typically 8-12 ohms at 20°C). Then verify the ECM is supplying 12-24V DC to the solenoid when commanded. If voltage is present but solenoid resistance is out of range, replacement is necessary.

Step 4: Perform Wiggle Test
With the ignition on (engine off), gently flex the wiring harness while monitoring live data. If the fault becomes active during harness movement, you've confirmed a broken conductor or intermittent connection—common in machines with 5,000+ operating hours.

Disclaimer: This guide provides general diagnostic procedures. Always consult the official Komatsu PC360-7 service manual and consider professional evaluation for complex electrical issues, especially when warranty considerations exist.