Hitachi ZX520LCH-3 Fault Code 14105-2: Complete Diagnostic Guide

What is Hitachi ZX520LCH-3 Fault Code 14105-2?

Fault Code 14105-2 indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically a CAN (Controller Area Network) bus communication error between the engine ECM and the machine's main controller. This code triggers when the ECM detects an abnormal signal or complete loss of data transmission on the CAN bus network.

In the ZX520LCH-3, the CAN communication system is critical for coordinating engine performance with hydraulic demands, monitoring systems, and operator display functions. When this circuit fails, the machine cannot properly integrate engine output with work functions, potentially causing reduced performance or complete operational shutdown. This is particularly problematic in used excavators where wiring harnesses and connectors have experienced years of vibration and environmental exposure.

Common Symptoms

• Warning light illuminated on the instrument cluster with reduced engine power (derate mode)
• Intermittent or complete loss of engine data on the monitor display (RPM, coolant temperature, fuel level)
• Erratic engine response to throttle inputs or hydraulic load changes
• Multiple fault codes appearing simultaneously due to communication breakdown
• Machine may enter limp mode or fail to start in severe cases

Potential Causes

The most common technical causes for Code 14105-2 in used ZX520LCH-3 excavators include:

• Damaged or corroded CAN bus wiring harness, particularly at flex points near the engine mount or cab pivot where cables experience repeated bending
• Loose or corroded connectors at the ECM or main controller, especially the 120-pin ECM connector known for moisture intrusion
• Failed termination resistors on the CAN network (typically 120-ohm resistors at network endpoints)
• ECM internal failure or corrupted software, more common in machines with 8,000+ operating hours
• Voltage supply issues to the ECM causing intermittent communication dropout
• Aftermarket modifications or improper repairs that compromised CAN bus shielding

How to Troubleshoot and Fix Code 14105-2

Step 1: Visual Inspection Begin with a thorough inspection of all wiring harnesses between the engine ECM (located on the right side of the engine) and the main controller. Check for chafing, cuts, or burn marks, especially where harnesses pass through bulkheads or near hot exhaust components. On used excavators, pay special attention to connector pins for corrosion or bent terminals.

Step 2: Electrical Testing Using a digital multimeter, verify CAN bus voltage at the ECM connector. With ignition on, you should measure approximately 2.5V on both CAN-High and CAN-Low lines at rest. Check termination resistance by measuring between CAN-High and CAN-Low with power off—you should read approximately 60 ohms (two 120-ohm resistors in parallel). Deviation indicates open circuits or failed resistors.

Step 3: Advanced Diagnostics Connect Hitachi Dr.EX diagnostic software or compatible scan tool to monitor live CAN bus traffic. Check for communication errors, message timeouts, or voltage anomalies. Perform a wiggle test on harnesses and connectors while monitoring for intermittent faults. If software shows ECM communication but Code 14105-2 persists, suspect ECM internal failure requiring replacement or reprogramming.

Step 4: Repair and Verification Replace damaged harnesses using OEM-spec shielded cable, ensuring proper grounding. Clean all connector contacts with electrical contact cleaner and apply dielectric grease. After repairs, clear codes and perform a full operational test under load to confirm stable communication.

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Disclaimer: This guide provides general diagnostic information. Complex electrical issues should be diagnosed by qualified technicians with proper Hitachi diagnostic equipment. Always consult the official service manual and follow safety protocols when working on heavy equipment.