What is Hitachi ZW310-5A Fault Code 111700-6?

Fault Code 111700-6 on the Hitachi ZW310-5A wheel loader indicates a communication error or malfunction in the machine's electronic control system, specifically related to the CAN (Controller Area Network) bus communication between the engine ECM (Engine Control Module) and the main machine controller. This diagnostic trouble code signals that critical operational data is not being properly transmitted between control modules, which can severely impact machine performance and safety systems.

This code is particularly critical for the ZW310-5A because this model relies heavily on integrated electronic systems for engine management, hydraulic control, and monitoring functions. When CAN bus communication fails, the machine's controllers cannot coordinate properly, leading to reduced operational capability or complete shutdown to prevent equipment damage. The ZW310-5A's Isuzu engine management system must maintain constant communication with the machine's main controller for optimal fuel injection timing, hydraulic response, and emission controls.

Common Symptoms

When fault code 111700-6 is active, operators typically experience:

• Dashboard warning lights illuminated, particularly the master caution light and engine malfunction indicator
• Engine derate or limp mode, with power output limited to approximately 50-60% of normal capacity
• Erratic gauge readings or complete loss of instrument cluster functionality, including fuel level, temperature, and hour meter displays
• Hydraulic system limitations, with slow or unresponsive loader or attachment controls due to lost communication with valve controllers
• Difficulty starting or intermittent engine stalling, especially during cold starts or after periods of inactivity

Potential Causes

The most common technical causes for code 111700-6 on used ZW310-5A machines include:

• Corroded or damaged CAN bus wiring harness connectors, especially at junction points near the engine compartment where exposure to heat, oil, and vibration is highest
• Broken or frayed CAN bus wires (typically twisted orange/green pair) at known rub points under the operator cab or along the main chassis harness
• Faulty ECM or machine controller, though less common than harness issues in used equipment
• Poor ground connections at main grounding points, which can disrupt low-voltage signal transmission
• Water intrusion into electrical connectors, particularly in machines operated in wet conditions or subjected to high-pressure washing
• Failed termination resistors at either end of the CAN bus network (typically 120-ohm resistors)

How to Troubleshoot and Fix Code 111700-6

Step 1: Visual Inspection of CAN Bus Harness Begin with a thorough physical examination of all wiring harnesses between the engine ECM (located near the engine firewall) and the main machine controller (typically under the operator seat). Look specifically for chafed insulation, broken wires, or oil-soaked sections. On used excavators, pay special attention to areas where harnesses pass through metal grommets or rest against moving components—these are common failure points. Check all connector pins for corrosion, bent terminals, or pushed-back pins that may not be making proper contact.

Step 2: Electrical Testing with Diagnostic Tools Using a digital multimeter, measure the resistance between the CAN-High and CAN-Low terminals at the ECM connector (usually pins 27 and 28 on the Isuzu engine harness). With ignition off and connectors attached, you should read approximately 60 ohms, indicating both 120-ohm termination resistors are present and the circuit is complete. If you read open circuit (OL) or significantly different values, there's a break or short in the CAN bus wiring. Next, check continuity of each CAN wire individually from ECM to controller with connectors disconnected—you should have less than 5 ohms resistance per wire.

Step 3: Controller and Software Verification Connect Hitachi Dr.EX diagnostic software or compatible scan tool to read freeze frame data and determine which controller is failing to communicate. Check for voltage supply to both ECM and machine controller—both should have battery voltage (12-14V) at power pins and solid grounds (less than 0.5 ohms to chassis). On used machines, verify ECM firmware versions are compatible and not corrupted. If all wiring tests pass but communication still fails, suspect controller failure, though harness issues account for approximately 80% of CAN bus faults in aging equipment.

Step 4: Repair and Prevention Replace any damaged harness sections with OEM-spec twisted-pair shielded cable rated for CAN bus applications (don't use standard wire). Apply dielectric grease to all connectors before reassembly to prevent future corrosion. Secure harnesses away from hot surfaces and moving parts using appropriate clamps. After repairs, clear codes and perform a complete operational test, monitoring for code recurrence over 30-60 minutes of varied operation.

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Disclaimer: This guide provides general troubleshooting information for educational purposes. Always consult the official Hitachi service manual for your specific machine serial number and consider engaging a certified Hitachi technician for complex electrical diagnostics. Improper repairs to electronic control systems can result in equipment damage or unsafe operating conditions.