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

Fault Code 14105-2 on the Hitachi ZX870-5A excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to the CAN (Controller Area Network) data link between the engine controller and the machine's main monitoring system. This code triggers when the ECM detects abnormal voltage levels, interrupted signals, or complete loss of communication on the CAN bus network.

This fault is critical because the ZX870-5A relies on continuous data exchange between multiple control modules to manage engine performance, hydraulic functions, and safety systems. When communication breaks down, the machine may enter a derate mode or experience erratic behavior that compromises productivity and safety on job sites.

Common Symptoms

• Warning lights illuminated on the instrument cluster, particularly the engine malfunction lamp or communication error indicator
• Intermittent or complete loss of digital display readings (RPM, coolant temperature, fuel level)
• Engine derate causing reduced power output or limited maximum engine speed
• Hydraulic system irregularities including sluggish response or inconsistent cycle times
• Multiple fault codes appearing simultaneously due to cascading communication failures across networked systems

Potential Causes

The most common causes of Code 14105-2 on used ZX870-5A excavators include:

• Corroded or damaged CAN bus connectors at the ECM or junction points, particularly the 8-pin communication harness connection behind the operator cab
• Wiring harness abrasion where cables run along the swing bearing or near hydraulic lines—a known wear point on high-hour machines
• Faulty ECM ground connections due to rust accumulation on mounting bolts or ground straps
• Water intrusion into sealed connectors from damaged grommets or failed environmental seals
• Failed terminating resistors on the CAN network (120-ohm resistors located at network endpoints)
• ECM internal failure from voltage spikes or age-related component degradation in older units

How to Troubleshoot and Fix Code 14105-2

Step 1: Visual Inspection Begin by thoroughly inspecting all wiring harnesses along the CAN communication circuit. Check for physical damage, particularly where harnesses contact metal edges near the turntable or engine mounting points. Examine all connectors for corrosion, bent pins, or moisture intrusion. Clean contacts with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing Using a digital multimeter, verify CAN bus voltage at the ECM connector. With ignition ON and engine OFF, measure between CAN-H and CAN-L terminals—you should read approximately 2.5V DC at rest. Check terminating resistor resistance by disconnecting both ends of the network and measuring between CAN-H and CAN-L; proper reading is 60 ohms (two 120-ohm resistors in parallel).

Step 3: Ground Circuit Verification Inspect and test all ECM ground connections. Remove ground bolts, clean contact surfaces with a wire brush, and verify less than 0.5 ohms resistance between the ECM ground and battery negative. On used excavators, corrosion at ground points is extremely common and often overlooked.

Step 4: Diagnostic Software Analysis Connect Hitachi Dr.EX diagnostic software or compatible scan tool to retrieve freeze frame data and monitor live CAN bus communication. Observe message traffic to identify which module is failing to communicate. This step helps isolate whether the issue is ECM-related or involves other networked controllers.

Step 5: Component Replacement If testing confirms a failed component, replace the ECM, damaged harness sections, or faulty connectors as needed. For used machines, always replace connectors and seals when replacing harnesses to prevent repeat failures.

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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 seek qualified professional assistance for complex electrical diagnostics and repairs.