Hitachi ZX850-3 Fault Code 11910-2: Complete Diagnostic Guide

What is Hitachi ZX850-3 Fault Code 11910-2?

Fault Code 11910-2 indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically a data link error or CAN bus communication failure between the engine controller and other machine systems. This code is part of Hitachi's proprietary diagnostic system and signals that critical operational data cannot be properly transmitted between control units.

The CAN (Controller Area Network) bus serves as the central nervous system for the ZX850-3, enabling real-time communication between the engine ECM, hydraulic controllers, and display monitors. When this communication breaks down, the machine cannot coordinate essential functions, potentially leading to reduced performance or complete shutdown. For this 85-ton excavator, maintaining reliable ECM communication is critical for fuel injection timing, hydraulic system coordination, and emission control compliance.

Common Symptoms

• Warning lights illuminated on the instrument cluster, particularly the engine malfunction indicator and communication error symbols
• Intermittent or complete loss of engine parameter displays (RPM, coolant temperature, fuel level) on the monitor
• Reduced engine power or activation of derate mode, limiting machine to low-idle operation
• Erratic hydraulic response due to loss of load-sensing coordination between engine and hydraulic systems
• Inability to access diagnostic information through the onboard display system

Potential Causes

The most common technical causes for Code 11910-2 on used ZX850-3 excavators include:

• Corroded or damaged CAN bus connectors, particularly at the ECM harness connection point behind the engine compartment
• Wiring harness chafing at known rub points near the engine mounting brackets and along the right-side frame rail
• Failed termination resistors within the CAN network (typically 120-ohm resistors at network endpoints)
• ECM power supply issues, including poor ground connections or voltage fluctuations from aging battery cables
• Water intrusion into connector seals, common in machines operating in wet conditions
• ECM internal failure or corrupted software, though less common than harness issues

How to Troubleshoot and Fix Code 11910-2

Step 1: Visual Inspection Begin with a thorough inspection of all wiring harnesses between the ECM and main junction box. On used excavators, focus on areas where harnesses contact frame members or pass through bulkheads. Look for abraded insulation, crushed wires, or green corrosion on connector pins.

Step 2: Connector and Resistance Testing Disconnect the ECM main connector and inspect for moisture, bent pins, or corrosion. Using a digital multimeter, measure resistance between CAN-High and CAN-Low terminals (typically pins 23 and 24 on the ZX850-3 ECM connector). You should read approximately 60 ohms with the system powered off, indicating proper termination resistors.

Step 3: Voltage and Signal Verification With the key in the ON position (engine off), measure voltage at the ECM power supply (should be 24V ±2V). Using Hitachi Dr.EX diagnostic software or compatible scan tool, monitor live CAN bus activity. Intermittent communication dropouts indicate harness issues rather than ECM failure.

Step 4: Harness Repair and Prevention For used machines, replace any suspect harness sections rather than attempting repairs with electrical tape. Apply dielectric grease to all reconnected terminals and secure harnesses away from heat sources and moving components using proper standoffs.

Disclaimer: This guide provides general diagnostic procedures. Complex electrical issues may require consultation with a certified Hitachi technician or authorized service center with access to complete wiring schematics and OEM diagnostic equipment.