What is Hitachi ZX870-5A (HCMC) Fault Code 14100-2?

Fault Code 14100-2 indicates a malfunction in the engine control system's communication circuit, specifically a CAN (Controller Area Network) communication error between the Engine Control Module (ECM) and the Hydraulic Control Module (HCM). This fault code is triggered when the ECM detects an abnormal signal or loss of communication on the CAN bus network that coordinates critical machine functions.

In the Hitachi ZX870-5A (HCMC) excavator, this communication pathway is essential for synchronizing engine power output with hydraulic demand. The CAN bus system allows real-time data exchange between control modules, ensuring optimal performance and fuel efficiency. When this communication fails, the machine's integrated control strategy cannot function properly, potentially leading to reduced productivity and premature component wear. This is particularly critical in the ZX870-5A, where the HCMC (Hitachi Construction Machinery Company) system relies on precise coordination between engine and hydraulic systems for heavy-duty applications.

Common Symptoms

• Warning light illumination on the instrument panel, specifically the engine diagnostic lamp or master caution light
• Reduced engine power (derate mode) where the excavator limits maximum RPM to protect components
• Erratic hydraulic response or sluggish boom/arm movements due to improper engine-hydraulic coordination
• Intermittent loss of functions, particularly during high-load operations or when multiple hydraulic circuits are engaged simultaneously
• Error messages displayed on the multi-information display indicating communication faults

Potential Causes

The most common technical causes for Code 14100-2 in used ZX870-5A excavators include:

• Damaged or corroded CAN bus wiring harness, especially at known rub points near the engine firewall and along the main chassis harness routing
• Faulty CAN bus termination resistors (typically 120-ohm resistors) that may deteriorate over time in high-vibration environments
• Corroded or loose connector pins at the ECM or HCM connection points, often caused by moisture intrusion in older machines
• ECM or HCM internal failure, though less common, can occur in high-hour machines exceeding 8,000-10,000 operating hours
• Voltage irregularities in the machine's electrical system, including weak batteries or failing alternators affecting CAN bus voltage stability
• Previous repair damage where harnesses were improperly routed or connectors not fully seated after maintenance

How to Troubleshoot and Fix Code 14100-2

Step 1: Visual Inspection and Connector Check Begin by thoroughly inspecting the CAN bus wiring harness from the ECM (located near the engine) to the HCM (typically mounted in the operator's cab area). Look for chafed wires, particularly where harnesses pass through bulkheads or contact metal edges. On used excavators, pay special attention to harness tie points that may have loosened over time, allowing wires to rub against moving components. Disconnect and inspect all relevant connectors for corrosion, bent pins, or moisture. Clean connectors with electrical contact cleaner and apply dielectric grease before reconnection.

Step 2: CAN Bus Electrical Testing Using a digital multimeter (DMM), measure the resistance between the CAN-High and CAN-Low terminals at the ECM connector with all modules disconnected. You should read approximately 60 ohms if termination resistors are functioning correctly (two 120-ohm resistors in parallel). Next, check for short circuits to ground on both CAN-High and CAN-Low wires—readings should show infinite resistance. With the key on and modules connected, measure CAN bus voltage between CAN-High and ground (should be approximately 2.5-3.5V) and CAN-Low and ground (should be approximately 1.5-2.5V). Significant deviations indicate wiring issues or module failures.

Step 3: Advanced Diagnostics and Module Testing Connect Hitachi Dr.EX diagnostic software or an equivalent OEM-level scan tool to access live data streams and communication status between modules. Monitor the CAN bus traffic to identify which module is failing to communicate. For used excavators with high hours, perform a power supply voltage check at both the ECM and HCM—ensure stable 24V DC supply with minimal fluctuation during engine cranking. If all wiring and voltage checks pass, the fault likely resides within one of the control modules. Before replacing expensive modules, verify that all software updates have been applied, as Hitachi has released firmware updates addressing communication protocol issues in some HCMC systems.

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Hitachi service manual for your specific machine serial number and software version. Complex electrical diagnostics may require factory-trained technicians with specialized equipment. Improper repairs can cause additional damage or safety hazards.