What is Hitachi ZW310-5A Fault Code 111700-9?

Fault Code 111700-9 on the Hitachi ZW310-5A wheel loader indicates a communication error or signal malfunction in the machine's electronic control system, specifically related to CAN bus network communication failures between the engine ECU (Electronic Control Unit) and other critical control modules. This diagnostic trouble code (DTC) signals that the primary controller is not receiving proper data packets from interconnected systems, disrupting coordinated machine operations.

In Hitachi's ZAXIS-5A generation equipment, the CAN (Controller Area Network) bus system serves as the backbone for all electronic communications between the engine management system, hydraulic controllers, transmission ECU, and instrument cluster. When code 111700-9 appears, it means there's an interruption in this vital communication pathway. This is particularly critical for the ZW310-5A because the integrated load-sensing hydraulics and auto-idle functions depend entirely on seamless data exchange between control modules. Prolonged communication failures can trigger limp mode, significantly reducing productivity and potentially causing uncoordinated responses between the engine and hydraulic systems.

Common Symptoms

• Check Engine Light (CEL) or master warning light illuminated on the instrument panel with possible audible alarm
• Erratic engine RPM or failure to respond to throttle inputs, particularly during combined operations
• Loss of auto-idle function where the engine doesn't reduce speed during inactive periods
• Hydraulic system derate with noticeably slower cycle times or reduced lifting capacity
• Instrument cluster displaying incorrect data or intermittent gauge readings (fuel level, coolant temperature, or hour meter)

Potential Causes

The most common technical failures triggering code 111700-9 on used ZW310-5A loaders include:

• Damaged CAN bus wiring harness due to physical abrasion, particularly at flex points near the engine bay or along the chassis rail where cables experience repeated movement
• Corroded or loose connectors at the main ECU harness junction, especially on machines operated in high-moisture or corrosive environments
• Failed termination resistors (120-ohm resistors) at CAN bus endpoints, common in equipment over 5,000 operating hours
• ECU internal failure or corrupted firmware in either the engine controller or secondary modules
• Voltage supply issues to control modules caused by failing alternators, weak batteries (below 12.5V), or poor ground connections
• Aftermarket accessory interference from improperly installed third-party electronics creating electrical noise on the CAN network

How to Troubleshoot and Fix Code 111700-9

Step 1: Preliminary Electrical System Check Begin with a comprehensive battery and charging system test. Using a digital multimeter (DMM), verify battery voltage reads 12.6-13.2V with the engine off and 13.8-14.4V at operating RPM. Check all battery terminal connections and main chassis ground points for corrosion or looseness. On used excavators, ground straps frequently corrode internally while appearing intact externally—physically remove and inspect grounding cables between the engine block, frame, and battery negative terminal.

Step 2: CAN Bus Physical Inspection Locate the main CAN bus wiring harness running from the engine ECU (typically mounted on the right side of the engine compartment) to the transmission controller and instrument cluster. Inspect the entire harness length for:

• Physical damage from rubbing against metal edges (common failure point near engine mounts)
• Connector pin corrosion at the Deutsch DT-series connectors used throughout Hitachi equipment
• Proper sealing of weatherpack connectors—water intrusion causes intermittent communication failures

Pay special attention to harness routing near moving components. In used machines, deteriorated mounting clips allow cables to contact hot exhaust components or rotating elements.

Step 3: CAN Bus Resistance Testing Disconnect the battery negative terminal before performing resistance checks. Using your DMM set to ohms (Ω), measure resistance between CAN-High and CAN-Low terminals at the engine ECU connector (consult service manual for specific pin locations—typically pins within the 60-pin main connector). You should measure approximately 60 ohms when the network is properly terminated with dual 120-ohm resistors at each end. A reading of 120 ohms indicates one missing termination resistor; infinite resistance suggests an open circuit in the wiring.

Step 4: Module Communication Test Using Diagnostic Software Connect Hitachi Dr.EX diagnostic software via the machine's diagnostic port (located in the cab, usually near the operator's seat). Run a complete system scan to identify which specific module is failing to communicate. The software will show network topology and identify whether the issue originates from the engine ECU, transmission controller, or instrument cluster. This step is essential for used machines as it prevents unnecessary component replacement.

Step 5: Connector Cleaning and Repair For machines exhibiting intermittent code 111700-9, the issue frequently lies in connector corrosion rather than harness damage. Disconnect each CAN bus connector, spray with electrical contact cleaner, and inspect pins for:

• Green/white corrosion deposits (indicating moisture intrusion)
• Bent or recessed pins that don't make solid contact
• Damaged connector seals allowing water entry

Clean all pins with a wire brush designed for electrical connectors and apply dielectric grease before reassembly to prevent future corrosion—especially critical in used equipment operating in dusty or wet conditions.

Step 6: ECU Replacement Considerations If all wiring, connections, and termination resistors test correctly, the fault likely resides in the engine ECU or another control module. Before replacing components, verify the ECU software version is current using diagnostic software—Hitachi released several firmware updates addressing communication stability for the 5A series. If ECU replacement becomes necessary, ensure the replacement unit is programmed with the correct machine configuration parameters, as generic ECUs won't function without proper initialization.

Critical Note for Used Equipment: On ZW310-5A loaders with over 8,000 hours, systematically replace all weatherpack connector seals in the engine bay before condemning electronic modules, as degraded seals are far more common failure points than actual ECU failures.

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Disclaimer: This guide provides general diagnostic procedures for Hitachi ZW310-5A fault code 111700-9. Always consult the official Hitachi service manual for your specific machine serial number and follow proper lockout/tagout procedures. If you lack experience with heavy equipment electrical systems or diagnostic software, consult a certified Hitachi technician to prevent further damage to electronic components.