What is Hitachi ZW310-5A Fault Code 111700-10?

Fault Code 111700-10 on the Hitachi ZW310-5A wheel loader indicates a hydraulic pump flow control solenoid circuit malfunction, specifically detecting an abnormal voltage or open circuit condition in the pump displacement control system. This code is triggered when the Electronic Control Module (ECM) detects voltage readings outside the acceptable range (typically 0.5-4.5V) for the proportional solenoid that regulates hydraulic pump displacement.

This fault is critical for the ZW310-5A because it directly affects the machine's ability to match hydraulic flow to operational demand. The variable displacement pump system relies on precise solenoid control to optimize fuel efficiency and hydraulic performance. When this code activates, the system typically defaults to a fixed displacement mode, significantly reducing operational efficiency and potentially causing overheating during demanding tasks.

Common Symptoms

• Reduced hydraulic power across all functions, particularly noticeable during bucket loading or boom operations
• Engine overspeeding or unusual RPM fluctuations when hydraulic functions are engaged
• Increased fuel consumption as the pump cannot reduce displacement during light-load conditions
• Warning light illumination on the instrument panel, often accompanied by a specific hydraulic system fault indicator
• Hydraulic oil temperature warning due to continuous full-flow operation without load-matching capability

Potential Causes

The most common causes for Code 111700-10 on used ZW310-5A machines include:

• Solenoid coil failure from heat cycling and contamination exposure over thousands of operating hours
• Wiring harness damage at known wear points near the hydraulic pump mounting area where cable routing creates friction against frame components
• Connector corrosion at the solenoid plug, particularly on machines operated in high-moisture or coastal environments
• ECM internal driver circuit failure, though less common, can occur in high-hour machines
• Intermittent short circuits caused by damaged wire insulation in the harness between the cab and pump assembly
• Poor ground connection at chassis grounding points affected by rust or loose mounting bolts

How to Troubleshoot and Fix Code 111700-10

Step 1: Initial Visual Inspection Disconnect battery power and thoroughly inspect the pump control solenoid connector for moisture, pin corrosion, or damaged seals. On used excavators, this connector often shows green corrosion on terminals. Check the wiring harness from the solenoid to the cab for obvious abrasion points, particularly where it passes near the swing bearing and along the frame rail.

Step 2: Solenoid Resistance Testing Using a digital multimeter, disconnect the solenoid connector and measure resistance across the solenoid terminals. Specifications typically call for 8-12 ohms at 20°C. Values significantly outside this range indicate solenoid coil failure requiring replacement. Also check for continuity to ground—there should be infinite resistance (open circuit).

Step 3: Circuit Voltage Testing Reconnect the harness and, with the key on (engine off), backprobe the ECM-side connector to measure supply voltage. You should see battery voltage (approximately 24V for this model). If voltage is absent, trace the circuit back toward the ECM, checking fuses, relays, and inline connections.

Step 4: Harness Continuity Check Perform a continuity test on each wire in the solenoid harness from the ECM connector to the solenoid connector. Wiggle the harness during testing to identify intermittent opens. Pay special attention to areas where harnesses bend sharply or contact metal edges.

Step 5: Signal Wire Testing (Advanced) If equipped with Hitachi diagnostic software (Dr.EX), monitor the solenoid command signal in real-time while commanding pump displacement changes. The voltage should vary smoothly between 0.5-4.5V. Erratic readings suggest ECM driver issues or poor grounds affecting the reference signal.

For used excavators specifically, always clean all connector pins with electrical contact cleaner and apply dielectric grease before reassembly, as corrosion is frequently the root cause rather than component failure.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Hitachi service manual for your specific machine serial number and software version. Complex electrical diagnostics should be performed by qualified technicians with proper training and calibrated equipment.