What is Komatsu PC450-7 Fault Code E246?

Fault Code E246 on the Komatsu PC450-7 indicates a malfunction in the pump control solenoid valve circuit, specifically related to abnormal current flow in the hydraulic pump's electronic control system. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects either an open circuit, short circuit, or improper resistance within the pump flow control solenoid valve wiring or the valve itself.

The PC450-7's sophisticated hydraulic system relies on precision electronic pump control to match flow rates with demand, optimizing fuel efficiency and performance. When E246 appears, the excavator typically enters a derate mode or limp mode, limiting hydraulic functions to protect the machine from potential damage. Ignoring this code can lead to reduced productivity, excessive fuel consumption, and accelerated wear on hydraulic components.

Common Symptoms

• Hydraulic pump performance reduction with noticeably slower cycle times on boom, arm, and bucket operations
• Intermittent or constant warning light on the monitor panel, often accompanied by an audible alarm
• Loss of fine control during precision work due to erratic pump response
• Machine entering derate mode, limiting engine RPM to approximately 1,400-1,600 range
• Increased fuel consumption as the system compensates for improper pump control calibration

Potential Causes

The most common causes for E246 on used PC450-7 excavators include:

• Damaged or corroded wiring harness at known rub points near the pump mounting bracket or along the main chassis rail
• Failed pump control solenoid valve due to internal coil deterioration or contamination from hydraulic fluid breakdown
• Corroded connector pins at the X2 harness connector behind the operator cab (particularly common on machines operating in coastal or high-humidity environments)
• ECM internal fault or software corruption (less common but documented in machines with 8,000+ operating hours)
• Voltage supply issues from the main power distribution harness, especially on machines with aftermarket electrical modifications

How to Troubleshoot and Fix Code E246

Step 1: Initial Visual Inspection Begin by conducting a thorough inspection of the pump control solenoid valve wiring harness from the ECM to the hydraulic pump. On used excavators, pay particular attention to harness routing near the right-side track frame where vibration-induced chafing commonly occurs. Check all connector terminals for green corrosion, bent pins, or moisture intrusion.

Step 2: Electrical Testing Using a quality digital multimeter, disconnect the pump control solenoid valve connector and measure resistance across the solenoid terminals. Specification should be 3.0-4.5 ohms at 20°C (68°F). Next, check for supply voltage at the connector with the ignition on—you should see approximately 12 volts. Any deviation indicates harness damage or ECM malfunction.

Step 3: Solenoid Valve Function Test If resistance and voltage readings are correct, connect Komatsu's KOMTRAX diagnostic software or an aftermarket tool compatible with the SAA6D125E-3 engine platform. Monitor real-time solenoid current draw during operation—normal current should range between 450-650 mA. Abnormal readings confirm valve replacement is necessary.

Step 4: Connector and Harness Repair For used machines, repairing corroded connectors or abraded wiring often resolves E246 without expensive part replacement. Use dielectric grease on all reinstalled connectors and add protective wire loom at vulnerable rub points. Ensure proper ground connections at chassis mounting points, as poor grounds frequently cause intermittent E246 codes.

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Disclaimer: This guide provides general troubleshooting information for the Komatsu PC450-7 E246 fault code. Always consult the official Komatsu service manual for your specific machine serial number and seek assistance from a certified Komatsu technician for complex electrical diagnostics or hydraulic system repairs. Improper repairs can void warranties and create safety hazards.