Hitachi ZX870H-3 Fault Code 13308-2: Complete Diagnostic Guide

What is Hitachi ZX870H-3 Fault Code 13308-2?

Fault Code 13308-2 indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to CAN (Controller Area Network) bus communication errors or data transmission failures between the engine controller and other machine systems.

This diagnostic trouble code (DTC) signals that the ECM is detecting abnormal or interrupted communication on the CAN bus network, which is the digital nervous system connecting the engine controller, hydraulic controllers, and display monitors. For the ZX870H-3's Isuzu engine management system, reliable CAN communication is critical for coordinating fuel injection timing, hydraulic demand, and emission controls. When this code activates, the machine may enter a protective derate mode to prevent potential damage from uncoordinated system operations.

Common Symptoms

When fault code 13308-2 is active, operators typically experience:

• Intermittent or complete loss of dashboard display information (engine RPM, temperature, or hydraulic pressure readings)
• Engine power reduction or derate mode activation, limiting machine performance to 70-80% capacity
• Multiple simultaneous fault codes appearing due to communication loss between controllers
• Erratic hydraulic response or delayed implement movements as controllers fail to coordinate
• Warning lights illuminating on the instrument cluster, particularly the engine malfunction indicator

Potential Causes

The most common technical causes for code 13308-2 on used ZX870H-3 excavators include:

• CAN bus wiring harness damage from rubbing against frame components near the engine firewall or along the boom base—a known wear point on high-hour machines
• Corroded or moisture-contaminated connectors at the ECM or junction boxes, especially on machines operated in wet or coastal environments
• Failed termination resistors on the CAN network (typically 120-ohm resistors at network endpoints)
• ECM internal communication module failure due to voltage spikes or age-related component degradation
• Loose or damaged ground connections affecting the entire electrical system reference voltage
• Aftermarket accessory installations that improperly tap into the CAN network

How to Troubleshoot and Fix Code 13308-2

Step 1: Visual Inspection Begin with a thorough physical examination of the main wiring harness from the ECM to the instrument cluster. On used excavators, focus on areas where harnesses pass through bulkheads or near moving components. Look for abraded insulation, pinched wires, or evidence of previous repairs. Inspect all CAN bus connectors (typically green or yellow-coded) for corrosion, bent pins, or moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, verify CAN bus integrity. Measure resistance between CAN-High and CAN-Low terminals at the ECM connector (with harness disconnected and ignition off)—you should read approximately 60 ohms, indicating both 120-ohm termination resistors are present and functional. Check for short circuits to ground on both CAN lines; readings should show infinite resistance (open circuit).

Step 3: Diagnostic Software Analysis Connect Hitachi Dr.EX diagnostic software or compatible scan tool to access live CAN bus data. Monitor communication status between modules while wiggling harnesses to identify intermittent connections. Check for voltage levels on CAN-High (typically 2.5-3.5V) and CAN-Low (1.5-2.5V) during normal operation.

Step 4: Component Replacement If testing reveals damaged wiring, repair or replace the affected harness section using proper CAN-rated twisted-pair cable. Clean all connectors with electrical contact cleaner and apply dielectric grease. For used machines with persistent issues after harness repair, consider ECM replacement or professional ECM testing, as internal communication modules can fail in high-hour applications.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Hitachi service manual for your specific machine serial number and consider professional assistance for complex electrical diagnostics. Improper repairs to CAN bus systems can cause additional controller damage.