Hitachi ZX870H-3 Fault Code 14105-2: Complete Diagnostic Guide

What is Hitachi ZX870H-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 controller.

This code triggers when the ECM detects an abnormal signal or complete loss of communication on the CAN bus network. The CAN bus is the critical digital highway that allows the engine controller, hydraulic controller, and display monitor to exchange real-time data. For the ZX870H-3's advanced Isuzu engine management system, this communication is essential for coordinating fuel injection timing, hydraulic load sensing, and emissions control. When this network fails, the machine cannot properly regulate engine performance relative to hydraulic demand, potentially causing unsafe operating conditions.

Common Symptoms

• Warning lights: Engine malfunction lamp illuminated on the monitor panel, often accompanied by a communication error message
• Engine derate: Automatic power reduction or engine speed limitation to protect components
• Erratic hydraulic response: Inconsistent boom/arm speed or loss of fine control due to ECM-hydraulic controller miscommunication
• Intermittent gauge failures: Tachometer, coolant temperature, or fuel level displays freezing or showing incorrect readings
• Multiple simultaneous fault codes: Additional codes appearing as various controllers lose synchronization

Potential Causes

• CAN bus wiring damage: Harness chafing at known rub points near the engine firewall or along the right-side frame rail where cables route to the cab
• Corroded or loose connectors: The 9-pin ECM connector (C101) or main CAN bus junction connector behind the operator seat accumulating moisture or vibration damage
• Failed termination resistors: 120-ohm resistors at CAN network endpoints degrading in used machines (typically 5+ years old)
• ECM internal failure: Less common but possible in high-hour machines (8,000+ hours)
• Voltage supply issues: Low battery voltage or failing alternator causing CAN bus voltage to drop below 9V threshold

How to Troubleshoot and Fix Code 14105-2

Step 1: Visual Inspection Inspect all CAN bus harness routing from the ECM (located right side of engine) to the cab controller. Check for abraded insulation, particularly where harnesses pass through bulkheads. On used excavators, examine connector pins for green corrosion—common in machines operated in coastal or high-humidity environments.

Step 2: Electrical Testing Using a digital multimeter, measure CAN-High and CAN-Low wire resistance between ECM connector terminals (consult service manual for pin locations). You should read approximately 60 ohms with ignition off—indicating proper termination resistors. Check for short circuits to ground (should read >10kΩ). Verify battery voltage remains above 11.5V during cranking.

Step 3: Diagnostic Software Analysis Connect Hitachi Dr.EX diagnostic software or compatible scan tool. Monitor live CAN bus traffic and check communication status between controllers. Intermittent dropouts indicate wiring issues; complete absence suggests ECM failure or power supply problems.

Step 4: Component Replacement Replace damaged harness sections using OEM-spec shielded twisted-pair cable. Clean all connectors with electrical contact cleaner and apply dielectric grease. If termination resistors test faulty, replace at both network ends.

Disclaimer: This guide provides general diagnostic procedures. Always consult the official Hitachi service manual for your specific machine serial number. Complex electrical issues may require professional diagnosis with manufacturer-specific tools.