Hitachi ZW310-5A Fault Code 111703-6: Technical Guide

What is Hitachi ZW310-5A Fault Code 111703-6?

Fault Code 111703-6 on the Hitachi ZW310-5A wheel loader indicates a communication error or malfunction in the machine's CAN (Controller Area Network) bus system, specifically related to the transmission control module or hydraulic system controller.

This diagnostic trouble code (DTC) signals that the main ECM (Engine Control Module) has detected abnormal or interrupted data transmission between critical control units. The CAN bus network serves as the central nervous system for the ZW310-5A, coordinating engine performance, hydraulic functions, and transmission operations. When this communication fails, the machine cannot properly synchronize these systems, potentially leading to reduced performance or complete shutdown to prevent mechanical damage.

For the ZW310-5A's Isuzu engine and advanced hydraulic system, maintaining clear communication pathways is essential for optimal fuel efficiency, load sensing, and operator safety features.

Common Symptoms

When fault code 111703-6 is active, operators typically experience:

• Warning lamp illumination on the instrument cluster, often accompanied by a diagnostic message on the monitor display
• Transmission shifting issues including delayed engagement, harsh shifts, or failure to change gears
• Reduced hydraulic responsiveness or intermittent loss of hydraulic functions (boom, bucket, or auxiliary circuits)
• Engine derate mode activation, limiting RPM and power output to protect drivetrain components
• Intermittent system failures that may reset after key cycling but return during operation

Potential Causes

The most common technical causes for code 111703-6 on used ZW310-5A machines include:

• Corroded or damaged CAN bus connectors at the transmission control unit or main harness junction points
• Wiring harness chafing near the transmission housing where vibration causes conductor breakage (known vulnerability point on this model)
• Failed transmission control module (TCM) due to moisture ingress or component age
• Low voltage conditions from weak batteries or failing alternator affecting communication signal integrity
• ECM software corruption or outdated firmware versions incompatible with transmission controller
• Termination resistor failure at either end of the CAN bus network

How to Troubleshoot and Fix Code 111703-6

Step 1: Initial Visual Inspection Begin by inspecting all CAN bus harness connections from the ECM to the transmission control module. On used excavators, focus on harness routing near the engine-to-transmission bell housing where heat and vibration cause accelerated wear. Check for oil-soaked connectors, physical damage, or pin corrosion. Clean all connector pins with electrical contact cleaner and apply dielectric grease to prevent moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, verify battery voltage exceeds 24V (for dual 12V systems). Check CAN-High and CAN-Low wire resistance between the ECM and TCM—both should read approximately 120 ohms total with proper termination resistors installed. Measure continuity through each CAN wire separately with the system powered down; any infinite resistance indicates an open circuit requiring harness replacement.

Step 3: Advanced Diagnostics Connect Hitachi Dr.EX diagnostic software or compatible OBD scanner capable of reading proprietary manufacturer codes. Monitor live CAN bus traffic to identify which controller is dropping communication. Check for multiple fault codes that might indicate a ground fault or power supply issue affecting multiple modules simultaneously.

Step 4: Component Replacement Sequence For used machinery, address the most common failure points first: replace corroded connectors, then test the termination resistors (typically located at the ECM and final controller). If communication remains interrupted, swap the transmission control module after verifying replacement part compatibility with your machine's serial number range. Finally, consider ECM reflashing if all physical components test satisfactory.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Hitachi service manual for your specific machine serial number and seek professional diagnostic assistance for complex electrical issues. Improper repairs to CAN bus systems can cause cascading failures across multiple control modules.