What is Hitachi ZW310-5A Fault Code 111704-10?

Fault Code 111704-10 on the Hitachi ZW310-5A wheel loader indicates a "Swing Motor Overheat Protection - Moderately Severe Level" condition. This diagnostic trouble code (DTC) is triggered when the electronic control module (ECM) detects that the swing motor temperature has exceeded safe operating thresholds, activating a protective derate function to prevent catastrophic damage to hydraulic components.

This code specifically monitors the swing motor thermal sensor circuit and compares actual operating temperatures against programmed limits within the machine's hydraulic management system. For the ZW310-5A, this is critical because excessive heat in the swing motor typically indicates hydraulic oil degradation, component wear, or system inefficiencies that can rapidly escalate into expensive failures if left unaddressed. This model's swing system operates under high pressure and continuous duty cycles, making thermal monitoring essential for component longevity.

Common Symptoms

• Warning lamp illumination on the instrument cluster with reduced swing function speed (derate mode activated)
• Noticeably slower swing rotation or jerky movements during cab rotation operations
• Audible high-pitch whining from the swing motor assembly during operation
• Hydraulic oil temperature gauge reading abnormally high, often accompanied by burnt oil smell
• Intermittent fault code appearance that may clear after cool-down periods but returns under load

Potential Causes

The most common technical causes for Code 111704-10 on used ZW310-5A machines include:

• Degraded hydraulic oil with insufficient cooling properties due to extended service intervals or contamination
• Faulty swing motor temperature sensor (resistance drift common after 5,000+ operating hours)
• Restricted hydraulic oil cooler fins clogged with debris reducing heat dissipation efficiency
• Worn swing motor internal components creating excessive friction and heat generation
• Damaged wiring harness at the swing post rotary joint where cable flexing causes conductor breakage
• Hydraulic system pressure imbalances forcing the swing motor to work harder than designed
• Failed swing relief valve causing pressure spikes and thermal buildup

How to Troubleshoot and Fix Code 111704-10

Step 1: Visual Inspection and Data Capture Connect Hitachi Dr.EX diagnostic software or compatible scan tool to retrieve freeze frame data showing exact temperature readings when the code set. Inspect the swing motor housing for external damage, oil leaks, or excessive dirt accumulation that restricts airflow cooling.

Step 2: Test Temperature Sensor Circuit Locate the swing motor temperature sensor connector (typically a 2-pin connector on the motor housing). Using a digital multimeter, check sensor resistance—specification is typically 2.4-2.6 kΩ at 20°C ambient temperature. Inspect connector pins for corrosion (extremely common on used machines) and check wiring continuity back to the ECM. On ZW310-5A models, pay special attention to the rotating electrical collector where harness fatigue often occurs.

Step 3: Hydraulic System Analysis Test hydraulic oil quality with a contamination analysis kit—viscosity breakdown and metal particles indicate internal wear. Check hydraulic oil cooler performance by measuring temperature differential across inlet/outlet (should be 15-25°C drop). Measure system pressure during swing operations; specifications should be 320-350 bar maximum.

Step 4: Component Testing Under Load If sensor and oil check normal, perform swing motor case drain flow test. Excessive case drain flow (>6 L/min at rated pressure) indicates internal wear requiring motor rebuild or replacement—common in machines exceeding 8,000 hours.

Disclaimer: This guide provides general diagnostic information. Always consult the official Hitachi service manual for your specific machine serial number and consider professional diagnosis for complex hydraulic system issues.