What is Hitachi ZX870-5A (HCMC) Fault Code 14105-2?

Fault Code 14105-2 indicates an abnormal signal or electrical malfunction in the engine control system's communication circuit, specifically related to the Engine Control Module (ECM) CAN (Controller Area Network) bus communication error. This code triggers when the ECM detects inconsistent or interrupted data transmission between critical control modules within the machine's electronic network.

On the Hitachi ZX870-5A (HCMC) excavator, this fault directly affects the machine's ability to coordinate engine performance, hydraulic functions, and safety systems. The CAN bus serves as the central nervous system for electronic communication, and any disruption can lead to degraded performance or complete operational shutdown. This is particularly critical in this large-class excavator where precise coordination between systems is essential for safe operation and productivity.

Common Symptoms

When fault code 14105-2 is active, operators typically experience:

• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Reduced engine power or activation of derate mode, limiting machine performance to protect components
• Erratic hydraulic response or delayed reactions to joystick inputs due to communication lag
• Intermittent gauge readings or complete loss of display information on the monitor panel
• Difficulty starting or unexpected engine shutdown during operation

Potential Causes

The most common technical reasons for code 14105-2 on used ZX870-5A excavators include:

• Corroded or damaged CAN bus wiring harness connections, especially at junction points near the engine bay where exposure to heat and vibration is highest
• Failed termination resistors within the CAN network causing signal reflection and data corruption
• Faulty ECM internal circuits or corrupted software requiring module reprogramming or replacement
• Damaged wiring harness due to rubbing against frame components, particularly along the undercarriage routing path—a known wear point on high-hour machines
• Poor ground connections at the ECM or related control modules causing voltage fluctuations
• Water intrusion into connector housings from damaged seals or cab leaks

How to Troubleshoot and Fix Code 14105-2

Step 1: Visual Inspection Begin with a thorough physical inspection of all CAN bus harness connectors between the ECM, display panel, and other control modules. On used excavators, pay special attention to connector pins for corrosion (green/white deposits) and check rubber boots for cracks. Inspect the wiring harness routing for signs of chafing or heat damage, especially where harnesses pass near the turbocharger or exhaust components.

Step 2: Electrical Testing Using a digital multimeter, measure the CAN-High and CAN-Low resistance between the ECM connector terminals (typically pins should show 60 ohms ±5 ohms with ignition off). Check for proper termination resistor values at network endpoints. Verify ground circuit integrity by measuring resistance from ECM ground to battery negative—readings above 1 ohm indicate poor grounding requiring cleaning or replacement.

Step 3: Diagnostic Software Analysis Connect Hitachi Dr.EX diagnostic software or an equivalent diagnostic tool to read detailed fault data and freeze frame information. Check for multiple simultaneous codes which may indicate a systemic wiring issue versus a single component failure. Perform an ECM communication test to identify which specific module is dropping off the network.

Step 4: Component Testing and Repair If wiring and connections test properly, the ECM itself may require software reflashing or replacement. Before replacing expensive modules on used equipment, always verify battery voltage (should be 24-28V on this model) and alternator output as low voltage can cause false communication errors. Replace any damaged harness sections with OEM-spec shielded cable to prevent future issues.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific machine serial number and consider professional diagnosis for complex electrical issues. Improper repairs to CAN bus systems can cause additional damage to electronic modules.